ADVERSE NEONATAL OUTCOMES IN RELATION TO PRENATAL RISK FACTORS

1 LITHUANIAN UNIVERSITY OF HEALTH SCIENCES

ACADEMY OF MEDICINE FACULTY OF PUBLIC HEALTH

Isha Chauhan

ADVERSE NEONATAL OUTCOMES IN RELATION TO PRENATAL RISK FACTORS

Master thesis (Public health)

Student Supervisor

Isha Chauhan Assoc. Prof. PhD Regina Mačiulevičienė

KAUNAS, 2017

2

SUMMARY

Public Health

ADVERSE NEONATAL OUTCOMES IN RELATION TO PRENATAL RISK FACTORS Isha Chauhan

Supervisor - Assoc. prof. MD PhD Regina Mačiulevičienė

Faculty of Public Health, Medical Academy, Lithuanian University of Health Sciences. Kaunas;

2017. 75 p.

Aim of study. To study the adverse neonatal outcomes in relation to prenatal risk factors among just delivered women in the department of Obstetrics and Gynecology in Kaunas Clinics.

Objectives. 1. To describe demographic characteristics of women who gave birth from 2015 to 2016 in Kaunas Clinics. 2. To analyse lifestyle and prenatal risk factors of respondents. 3. To analyse correlation between adverse neonatal outcome, lifestyle and risk factors

Methodology. A preformed questionnaire was given to 406 women after delivery and 349 questionnaires were returned back. 39 women were excluded from the study due to non availability of record, anonymity and incomplete information. The study was carried out among 310 women.

Women were assessed in detail regarding their demographic profile, socioeconomic history, past obstetric/ medical and personal history and lifestyle. History of type of birth and significant labor events were obtained through hospital records.Base-line characteristics of neonates and morbidities (if any) were also recorded. These were characteristics like weight,APGAR score, gestational age and adverse neonatal outcomes which included preterm birth (PTB), low birth weight (LBW) macrosomia, large for gestational age (LGA), small for gestational age (SGA) dysplasia fetus and infections with the help of hospital records.The women under investigation were then divided into 2 groups and they were studied with statistical analysis - cases - women who delivered baby with adverse neonatal outcome and controls - women who delivered baby without adverse neonatal outcome . Statistical analysis was performed with Statistical package for social sciences (SPSS) 20.

Means, Standard deviation, Pearson's chi square test, leveny's test for equality of variance , t- test and Cramer’s V were used.

Results. This study involving 349 women, is a cross sectional – case control study. Out of 349, 310 women were analyzed for adverse neonatal outcomes. The adverse neonatal outcomes included preterm birth (PTB) (41%), low birth weight (LBW) (36.1%), macrosomia (24.6%), large for gestational age (LGA) (22.1%), small for gestational age (SGA) (15.6%), dysplasia fetus (8.2%), infections (0.8%) and hydrocephalus (0.8%). More than one adverse outcome may be present in a neonate. The risk of adverse neonatal outcomes were higher in women with polyhydramnios (OR=

5.6 [95% CI 1.1 to 27] ), hepatobiliary diseases (OR= 9.6 [95% CI 1.1 to 81] ), adiposity (OR= 4.9

[95% CI 1.3 to 18] ). Lifestyle and prenatal risk factors were found to be correlated with adverse

3 outcomes. Higher risk of PTB due to vaginal bleeding (during hospital admission in pregnancy) (OR= 11.5 [95% CI 1.3 to 97.1] ); LBW due to heavy illness (OR=12.1 [95% CI 1.4 to 104.6] ) and vaginal bleeding (OR= 6 [95% CI 1.1 to 31.1] ); SGA as a result of walking 6 km or more each day during pregnancy (nature of work) (OR= 4.2 [95% CI 1.06 to 16.7] ), anemia (OR= 3.1 [ 95% CI 1.08 to 9.2] ) and allergy (OR= 3.7 [ 95% CI 1.09 to 12.7] ) in mothers and primary hypertension (OR= 4.2[ 95% CI 1.06 to 16.7] ); LGA due to work in morning and day shift (before pregnancy) (OR= 3.7 [ 95% CI 1.2 to 11] )(during pregnancy) (OR= 3.2 [ 95% CI 1.08 to 9.7] ); and macrosomia due to follow of diet (OR= 4.4 [ 95% CI 1.09 to 17.6] ), were found.

Conclusions. Lifestyle and prenatal risk factors are positively associated with adverse neonatal outcomes.

Key words: risk factors, adverse neonatal outcome, demographic characteristics, lifestyle related

factors.

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CONTENTS

ABBREAVIATIONS. ...5

INTRODUCTION ...6

1. AIM AND OBJECTIVES OF THE WORK ...8

2. REVIEW OF LITERATURE 2.1 Demographic Characteristics ...9

2.2 Maternal Chronic diseases ...12

2.3 Nutrition and Lifestyle ...17

3. RESEARCH METHODOLOGY ...24

4. RESULTS 4.1 Demographic characteristics of case and control groups ...28

4.2 Lifestyle and prenatal risk factors of respondents ...31

4.3 Spectrum of adverse neonatal outcomes ...40

4.4 Correlation between risk factors and adverse outcomes ...42

5. DISCUSSION ...52

6. CONCLUSIONS ...56

7. PRACTICAL RECOMMENDATIONS ...57

8. REFERENCES ...58

9. SUPPLEMENTS 9.1 Bioethics permission ...64

9.2 Questionnaire and consent form ...65

9.3 Hospital record ...72

9.4 Weight percentile chart ...73

5

ABBREVIATIONS

AED – Antiepileptic drug AMA – Advanced maternal age ANO – Adverse neonatal outcome BMI – Body mass index

CKD – Chronic kidney disease FPG – Fasting plasma glucose DM – Diabetes mellitus GA – Gestational age

GDM – Gestational diabetes mellitus HTN – Hypertension

IUGR – Intrauterine growth retardation LGA – Large for gestational age LBW – Low birth weight

PIH – Pregnancy induced hypertension PTB – Preterm birth

RDS – Respiratory distress syndrome

SCH – Subclinical hypothyroidism

SGA – Small for gestational age

SIDS – Sudden infant death syndrome

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Introduction

It all starts from fertilization of ovum by sperm, that formation of human embryo begins. In just around 14 days, the ovum is well differentiated into amnion and yolk sac cavities [1]. The growth of the fetus in utero continues in well predetermined way in established 3 trimesters.

Delivery of fetus that is capable of surviving successfully in the extra uterine environment, is the ultimate desire of every obstetrician. It is variations in materno-fetal interactions, through human placenta that not only produces varied outcomes of pregnancy, but also determines development of adult disease.[2]. The health of neonates depends on the health of the mother. Following are risk factors associated with adverse neonatal outcomes: Maternal age, Maternal obesity, Low socioeconomic status, Maternal chronic diseases (Diabetes, Hypertension and preeclampsia, Kidney disease, Thyroid dysfunction, Epilepsy, Psychiatric diseases), Nutrition, Short interpregnancy intervals, Prenatal Care, Substance abuse Smoking, Alcohol, tobacco, History of complications during previous delivery, Familial history of genetic disorder, Shift work and Domestic violence.

Maternal demographic factors like age, body weight and socioeconomic status can affect the

outcomes of pregnancy. Teenage pregnancy may lead to low birth weight and preterm infants as the

mother’s body is still in growing stage and is not fully developed. On the other hand, advanced

maternal age (more than 35 years) also increases risk of preterm delivery, low birth weight and

genetic abnormalities. Socioeconomic status such as low education level, poverty, place of

residence, low income increase incidence of neonatal mortality along with low birth weight and

prematurity. Poor health, lack of good nutrition, lack of access to healthcare services and poor

living conditions may be contributors for increased risk of adverse neonatal outcomes (ANO). Pre-

pregnancy health status such as presence of diabetes, hypertension, anaemia, epilepsy, kidney

disease, thyroid dysfunction severely affect the health of neonates due to pathophysiological effects

on the foetus. In addition to physical health, mental health of women of childbearing age is also

indispensable for a healthy child. Mood and anxiety disorders are highly prevalent among women of

reproductive age. Psychiatric illness during pregnancy increase risk of postpartum psychiatric

illness, increased substance abuse, and lower involvement in prenatal care which can adversely

affect the growth of infant. Women with prior complicated pregnancy may deliver low birth weight

baby and preterm delivery. Nutrition is also one of the major determinant of maternal and neonatal

outcomes. Lack of protein and micronutrients like vitamins, zinc, selenium may lead to

malformation of the foetus. Insufficient nutrition leads to low weight gain which increases risk of

complications. Exposure to toxic and hazardous materials during pregnancy is another risk factor of

malformations [3].

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The topic of adverse neonatal outcomes is quite broad, where the major outcomes observed in

recent times are stillbirth, neonatal death, Intrauterine Growth restriction, prematurity, congenital

abnormalities, large for gestational age, small for gestational age and various infections [3].

8

1. AIMS AND OBJECTIVES

Aim: To study adverse neonatal outcomes in relation to prenatal risk factors among just delivered women in the department of Obstetrics and Gynecology in Kaunas Clinics.

Objectives:

1. To describe demographic characteristics of women who gave birth from 2015 to 2016 in Kaunas Clinics.

2. To analyse lifestyle and prenatal risk factors of respondents.

3. To analyse correlation between adverse outcome of pregnancy, lifestyle and risk factors.

9

2 LITERARURE REVIEW 2.1. Demographic characteristics

2.1.1. Maternal age

In the last decade, average age of pregnancy has increased 26 years compared to 23 years earlier.

Risk of adverse neonatal outcomes increases with increase in age. Kahalil et al conducted a retrospective study to assess the association between maternal age and adverse pregnancy outcomes.

The study included 76158 singleton pregnancies with a live fetus at 11 + 0 to 13 + 6 weeks.

Maternal age ≥ 40 years was associated with increased risk of miscarriage, pre-eclampsia, gestational diabetes mellitus (GDM), small-for-gestational age (SGA) neonate and Cesarean section, but not with stillbirth, gestational hypertension, large-for-gestational age (LGA) neonate, spontaneous preterm delivery [4].

29760 singleton pregnancies were assessed by Koo YJ et al, which were delivered between the years 2005 and 2008 for the effect of advanced maternal age (AMA) on the perinatal and obstetric outcomes. Patients were categorized into four groups according to age: 20-29 years, 30-34 years, 35-39 years, and ≥40 years. Adverse perinatal outcomes such as low birth weight, Apgar score < 7 at 1 minute and chromosomal anomaly were seen in maternal age ≥35 years [5].

Carolan conducted a review of effect of very advanced maternal age (≥45 years) on maternal and perinatal outcomes in high-income countries.6 Three main findings were 1.)Increased rates of stillbirth, perinatal death, preterm birth and low birth weight among women ≥45 years 2) increased rates of pre-existing hypertension and pregnancy complications such as GDM, gestational hypertension, pre-eclampsia and interventions such as caesarean section 3) Favorable outcomes in extremely advanced maternal age (50-65 years) who were healthy. There are conflicting results about increased maternal age on adverse effect on neonates. However, it is associated with adverse maternal outcomes [6].

2.1.2. Maternal BMI

Incidence of obesity among women of childbearing age has increased over the years. Maternal obesity before pregnancy may have an influence on both obstetrical and neonatal outcomes.

Blomberg conducted a cohort study including 1024471 women to assess adverse neonatal outcome due to maternal obesity. Neonates born to women with BMIs of 40 or more (morbidly obese) were found to be at increased risk of birth injury to the peripheral nervous system, birth injury to the skeleton, sepsis, respiratory distress syndrome, convulsions, and hypoglycemia [7].

Another study by Crane et al using the Newfoundland and Labrador Perinatal Database assessed

effects of extreme obesity (pre-pregnancy BMI ≥ 50.0 kg/m2) in pregnancy on maternal and

perinatal outcomes. They found that extreme obesity was significantly associated with birth weight

10

≥ 4000 g, birth weight ≥ 4500 g, neonatal metabolic abnormality, NICU admission, stillbirth and composite adverse outcome in neonates [8].

A similar retrospective U.S. cohort study, Kim et al evaluated the effect of obesity among obese mothers without chronic diseases (N=112,309). Preterm birth at less than 32 weeks of gestation, large for gestational age (LGA), transient tachypnea, sepsis, and intensive care unit admission increased proportionately with maternal BMI status [9].

Scott-Pillai et al conducted a retrospective study in UK obstetric population, between 2004-2011 to evaluated impact of body mass index on maternal and neonatal outcomes. Neonatal outcomes are presented in Table 2.1.1. Risk of preterm delivery, stillbirth, postnatal stay > 5 days, and infant requiring admission to a neonatal unit was more in women in obese class III. Also, adverse outcomes like low birth weight and macrosomia were seen in another category: - Underweight women. So, BMI which is far away to either ends from normal BMI range tends to witness major part of total adverse outcome [10].

Table 2.1.1. Neonatal outcomes in obese pregnant women (According to Scott-Pillai R et al., 2013)

Un derweight

BMI

<18.50 n = 862

Normal BMI 18.50–

24.99 n = 15 908

Overweigh

t BMI

25.00–

29.99 n = 8 415

OBESE CLASS I BMI 30.00–

34.99 n = 3 333

OBESE CLASS II BMI 35.00–

39.99 n = 1 194

OBESE CLASS III

BMI ≥ 40.00 n = 586

P

(unadjusted/adju sted)

Gestation <37 weeks (preterm)a

1 750

1.2 (0.9–1.8)

0.150

1.00 1.

1 (1.0–

1.3) 0.036

1.

3 (1.0–

1.6) 0.004

1.

3 (0.9–

1.7) 0.079

1.6 (1.1–2.5) 0.003

0.012/0.

002 Gestation >41 we

eksa

9 07

0.5 (0.2–1.0)

0.016

1.00 0.

9 (0.7–

1.1) 0.170

0.

8 (0.5–

1.1) 0.047

0.

9 (0.5–

1.6) 0.681

0.8 (0.4–1.7) 0.396

0.693/0.

077 Low birthweight

(<2.5 kg)b

1 491

1.6 (1.0–2.4)

0.010

1.00 0.

8 (0.6–

1.0) 0.010

0.

7 (0.5–

1.0) 0.007

0.

5 (0.3–

0.9) 0.002

0.5 (0.2–1.0) 0.011

0.004/<

0.001 Macrosomia

(>4.0 kg)b

4 391

0.5 (0.3–0.7)

0.001

1.00 1.

5 (1.3–

1.6)

<0.001

1.

9 (1.6–

2.2)

<0.001

2.

1 (1.7–

2.6)

<0.001

3.2 (2.4–4.1)

<0.001

<0.001/

<0.001

Stillbirth 1

26

2.0 (0.6–6.0)

0.125

1.00 1.

5 (0.9–

2.5) 0.054

0.

8 (0.3–

2.0) 0.528

2.

2 (0.9–

5.7) 0.027

3.0 (1.0–9.3) 0.010

0.055/0.

013

Cardiac defect 5

4

1.1 (0.1–16.6)

0.903

1.00 0.

8 (0.3–

2.3) 0.574

0.

5 (0.1–

3.5) 0.400

3.

7 (1.0–

14.2) 0.014

2.1 (0.2–19.2)

0.406

0.069/0.

105

Neural tube defect

2 5

– 1.00 1.

6 (0.4–

7.1) 0.408

1.

1 (0.1–

10.2) 0.904

7.

5 (1.2–

46.5) 0.004

– 0.036/0.

127

Apgar <7 at 5 minutes

6 23

1.4 (0.8–2.4)

0.118

1.00 1.

1 (0.9–

1.4) 0.241

1.

0 (0.7–

1.4) 0.985

0.

9 (0.5–

1.6) 0.537

2.0 (1.1–3.6) 0.002

0.458/0.

024 Admissio

n to NNUc

1 675

1.1 (0.7–1.6)

0.751

1.00 1.

1 (0.9–13) 0.269

1.

3 (1.1–

1.7) 0.001

1.

6 (1.2–

2.2) 0.001

1.6 (1.0–2.6) 0.008

<0.001/

<0.001 Infant

stay >5 days

3 867

1.0 (0.7–1.3)

0.754

1.00 1.

0 (0.9–

1.1) 0.510

1.

0 (0.9–

1.1) 0.902

0.

9 (0.7–

1.1) 0.187

1. All variables are adjusted for age, parity, social deprivation, smoking, and year of birth. Values

presented as OR (99% CI), with P < 0.01 considered to be significant (shown in bold). See Table S2 for data presented with 95% CIs.

2. a Preterm and post-term also adjusted for elective caesarean section and induction of labour.

3. b Low birthweight and macrosomia also adjusted for gender and gestational age.

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4. c Admission to neonatal unit also adjusted for preterm delivery and both pre-existing and

gestational diabetes.

2.1.3. Socioeconomic status

Poor socioeconomic status such as low education level of the parents, less earning potential of the family, are found to increase the risk of adverse neonatal outcomes. Socioeconomic differences and birth outcomes can contribute to necessary information for various intervention programs. Luo et al studied association between socioeconomic status and adverse birth outcomes. Socioeconomic status was deciphered using individual-level measures (mother’s education) and community-level measures (neighborhood income). Data of all births from 1991 to 2000 from birth registration certificates was collected and linked to census enumeration areas. There was an elevated crude risk of preterm birth, small-for-gestational-age (SGA) birth, stillbirth and neonatal and post neonatal death with lower levels of maternal education and neighborhood income. Education of mother proved to be a stronger factor as compared to effect of neighborhood income [11].

A study by Smith assessed effect of socioeconomic inequalities in neonatal mortality associated with congenital anomalies. This retrospective population based registry study included population of East Midlands and South Yorkshire regions of England.

There was no evidence of variation in the overall risk of these anomalies with deprivation).

The rate of termination after antenatal diagnosis of a congenital anomaly was lower in the most deprived areas compared with the least deprived areas [12].

According to Yaya S et al, inadequate utilization of prenatal care services, socioeconomic status, and educational attainment are associated with LBW in Zimbabwe. The study performed was cross sectional data, and the data was obtained from Multiple Indicator Cluster Survey round 5 and was carried out in 2014. Participants included 3,221 mothers from both rural and urban areas.

Prevalence of LBW was 12.8%. Risk of LBW was 11% less in urban area when compared with rural area. In addition, risk of LBW in those having primary/below primary and secondary level qualification was 73 and 56%, respectively compared to women with higher education [13].

In one of the biggest study, socioeconomic and health system determinants of wealth-related

inequalities determining neonatal mortality rates across 48 low- and middle-income countries was

assessed. Demographic and health surveys were conducted between 2006 and 2012. Data was

assessed to determine if neonatal mortality rate was associated with inequalities in coverage of

maternal health services, country-level economic and health system factors and socioeconomic

inequality. The magnitude of socioeconomic inequality in neonatal mortality rate was most strongly

related to inequalities in antenatal care.They concluded that reducing the financial burden of

maternal health services and providing universal coverage of antenatal care may contribute to a

reduction of neonatal mortality rate [14].

12 In another study, socioeconomic inequality in neonatal mortality in 24 low-income and middle-income countries was analyzed. Data from demographic and health surveys done in 2008 or later (survey 1) and one about 10 years previously (survey 2) were compared. In most countries, absolute and relative wealth-related and educational inequalities in neonatal mortality rates decreased between survey 1 and survey 2. The difference in neonatal mortality rates between extreme ends of the wealth distribution, was lowered by more than two neonatal deaths per 1000 livebirths per year in five countries (Cameroon, Nigeria, Malawi, Mozambique, and Uganda).

However, difference in neonatal deaths between wealthy and poor increased in Ethiopia and Cambodia. They concluded that neonatal mortality rate has decreased among socioeconomic inequality in last 20 years, mainly among lower and middle income countries [15].

Dettrick et al analyzed the level of variations in under-five and neonatal mortality across by rural-urban location, ethnicity, wealth, and districts. Gap in the mortality trends in rural and urban areas is reducing, as the rate of change in urban areas is slower. In addition, difference in mortality between rich and poor households has decreased in both urban and rural areas. Child mortality is observed to be decreased steadily over the years in states such as Uttar Pradesh [16].

2.2. Maternal chronic diseases

2.2.1. Diabetes

With obesity as an increasing problem among women, in almost all countries worldwide, the risk of

development of type 2 diabetes and gestational diabetes among women also increases. Maternal

hyperglycemia causes adverse effect on the fetus leading to adverse effects in new-born babies. The

risks of adverse pregnancy outcomes differ depending on the glucose values among gestational

diabetes patients. Billionnet et al assessed the impact of gestational diabetes on adverse perinatal

outcomes from 716152 births in France. The risks of preterm birth, macrosomia, respiratory

distress, birth trauma and cardiac malformations were increased in women with gestational diabetes

compared with the non-diabetic population. Risk of adverse perinatal outcomes was higher in

insulin-treated gestational diabetes than in non-insulin-treated gestational diabetes for most

outcomes. Newborn baby born to women with GDM were at increased risk of death. This risk

moderately more in women with diet-treated GDM, with a 30% increased risk of the baby dying

than insulin treated women. This may be because GDM cases who are diet treated tend to give birth

later than those who are treated with insulin, meaning the unborn child is exposed to higher glucose

levels for longer period of time. One of the key results is that the risk of cardiac malformations in

infants is higher for women with insulin-treated GDM, whereas the risk of nervous system

anomalies is not. This result suggests that exposure of the embryo to high glucose levels has not so

13 similar effects on cardiac and nervous system tissues. In addition, the risk of respiratory distress is also increased for insulin-treated GDM women [17].

In a Mediterranean population study, there were adverse pregnancy outcomes in women with fasting plasma glucose (FPG) levels below those diagnostics of gestational diabetes according to the guidelines. There was positive association between FPG and large for gestational age and prematurity both <37 and <34 weeks of gestation and negative association between FPG and small for gestational age [18].

Pre-existing diabetes may also substantially increase risk of fetal and infant death in normally formed offspring. This effect is largely depends on level of glycemic control. Tennant PW et al conducted a population based study among women with pre-existingdiabetes(1206 with type 1 diabetes and 342 with type 2 diabetes) in the North of England during 1996-2008. Fetal death in women with diabetes was over four times greater than in those without diabetes, and infant death was almost double. Prevalence of fetal death or infant death among women with type 1 diabetes and women with type 2 diabetes was almost same. HbA1c concentration above 49 mmol/mol befor the conception, pre pregnancy retinopathy and lack of folic acid supplementation before pregnancy increased risk of fetal and infant death [19].

2.2.2. Hypertension Hypertension during pregnancy can be classified as [20].

• Pregnancy-induced hypertension is increase in blood pressure, without proteinuria, during the second half of pregnancy.

• Pre-eclampsia is associated with increase in blood pressure and proteinuria.

• Chronic hypertension in pregnant women is pre-existing hypertension in pregnant women.

Chronic hypertension complicates between 1% and 5% of pregnancies. Incidence of hypertension is increasing in pregnant women partly because of increased childbearing age. In addition, obesity and metabolic syndrome are likely to increase risk of hypertension. Several retrospective and prospective cohort studies, intervention trials, and observational studies have evaluated hypertension as a risk factor for complications of pregnancy in women. Family physicians, clinical pharmacologists, gynecologists, cardiologists, nephrologists, endocrinologists, and general physicians may be required for good control of hypertension in pregnant women.

Bramham K et al conducted a meta-analysis and systematic review of both retrospective and

prospective cohorts, population studies, and series of randomized controlled trials of pregnant

women with chronic hypertension. This meta-analysis included 55 eligible studies consisting of

795221 pregnancies. Study populations included those with superimposed pre-eclampsia, caesarean

section and preterm delivery were included in the review. The review included different study

populations, of superimposed pre-eclampsia, caesarean section, preterm delivery. Hypertension in

14 pregnancy was associated with preterm delivery before 37 weeks’ gestation, Low birth weight, perinatal death, and NICU admission. The consequences of these complications have both short term and long term health consequence for the offspring of women with chronic [20].

In another review conducted by Duley, management strategies of pre-eclampsia and pregnancy induced hypertension was analyzed based on published trials. The review included 53 systematic reviews, RCTs, or observational studies. They found that 10% of pregnancies are affected by pregnancy-induced hypertension, and 2-8% of pregnancies will have pre-eclampsia.

Eclampsia occurs in about 1/2000 deliveries in resource-rich countries. In resource-poor countries, it is found that the incidence of eclampsia varies from 1/100-1/1700. Pregnancy induced hypertension and pre-eclampsia were associated with mortality, intrauterine growth restriction, prematurity, and severe morbidity (such as intraventricular haemorrhage, respiratory distress syndrome, or asphyxia) [21].

Abalos et al conducted a study of the World Health Organization Multicountry Survey on Maternal and Newborn Health (WHOMCS) database to assess the incidence of hypertensive disorders of pregnancy and to compare the outcomes of mother and neonate with and without these conditions. Incidences of pre-eclampsia, eclampsia and chronic hypertension were found to be 2.16%, 0.28% and 0.29%, respectively. Cases such as pre-eclampsia were 8 times more frequent and with eclampsia were 60 times more frequent among near-miss mothers, than the mothers who were free from these conditions [22].

2.2.3. Kidney diseases

At least 4% of childbearing-aged women are affected by chronic kidney disease. Impaired

kidneys may fail to adapt to the normal physiologic changes during pregnancy, leading to adverse

outcomes. Diabetic nephropathy is the most common type of chronic kidney disease found in

pregnant women. However, other primary and systemic kidney diseases also occur in pregnant

women. In patients with mild chronic kidney disease (serum creatinine <1.3 mg/dL), kidney

function is unaffected in mothers and infants are not affected. In cases of moderate and severe

chronic kidney disease, there is a risk of accelerated irreversible decline in kidney function which in

turn increases risk of fetal prematurity, low birth weight, and death substantially. Maternal

hypertension and proteinuria complicate the situation and are important factors to consider. Bharti

et al conducted a retrospective study over a period of 11 years at the Department of Obstetrics and

Gynaecology, All India Institute of medical sciences, New Delhi. The study included 80 pregnant

women with chronic kidney disease (CKD). Incidence of preeclampsia and moderate to severe

anemia in late stage CKD was significantly more when compared to early stage. Patients with late

stage CKD had significantly increased incidence of small for gestational age, low 5 min Apgar

score and increased NICU admissions. There was increase in preterm delivery rate (57.5%) and

15 incidence of caesarean section rate (64%). They concluded that incidence of adverse events in foetus is high in pregnant women with CKD as compared to the general population [23].

Alsuwaida et al analyzed effect of early CKD using eGFR on outcomes of 98 pregnant women with CKD. Risk for intrauterine growth restriction, preterm birth, and intrauterine fetal death was more in women with an eGFR of 60-89. They were also at increased risk for deterioration of renal function, preeclampsia, and cesarean section. Use of estimated GFR than the serum creatinine alone may be better to assess risk of adverse outcomes in pregnant women with early CKD [24].

Feng et al compared the impact of maternal and fetal outcomes of pregnant women with advanced CKD with mild to moderate CKD in a retrospective, single-center study. Incidence of pre- term delivery were more in women with severe CKD than in women with mild CKD. However, incidence of perinatal death, oligohydramnios, and intrauterine growth retardation were similar in both groups. Risk of preterm delivery, small for gestational age, and decline of maternal renal function increases with a reduction in eGFR [25].

In another retrospective study comparing pregnant women with and without kidney disease by Kendrick et al, 778 women with kidney disease were included. Women with kidney disease had 52% increased risk of preterm delivery and 33% increased risk of delivery by caesarean section.

The incidence of foetal outcomes in women with and without kidney disease is shown in table 2.

Infants born to women with CKD were at 71% higher risk of admission to the neonatal intensive care unit or infant death compared with infants born to women without CKD. There was a 2-fold increased risk of low birth weight in infants [26].

Table 2.2.1. Adverse Fetal Outcomes in women with kidney disease (according to Kendrick et al;

2015)

Parameters Odds ratio (Confidence Interval) Low birth weight, ie <2500 g 2.38 (1.64 to 3.44)

SGA 1.37 (0.94 to 2.00)

Admission to NICU/infant death 1.71 (1.17 to 2.51)

Admission to NICU 1.80 (1.22 to 2.65)

Infant death 0.50 (0.05 to 5.51)

2.2.4. Thyroid diseases

Tong et al conducted a systematic review and meta-analysis using PubMed, Embase, and Cochrane

database to study the link between maternal subclinical thyroid dysfunction and the risk for

intrauterine growth restriction (IUGR). They found 13 cohort articles; Seven studies which

contained cases of subclinical hypothyroidism (SCH), 4 on subclinical hyperthyroidism, 7 on

positivity for thyroid peroxidase antibody (TPOAb), and 4 on isolated hypothyroxinaemia.

16 Subclinical hyperthyroidism, TPOAb positivity, or isolated hypothyroxinemia were not found to have any effect on IUGR. However, SCH is associated with IUGR [27].

Tudosa et al maternal-foetal complications during pregnancy in hypothyroidism-related pregnancy in a retrospective clinical-statistical study. Irregularities of foetus cardiac rhythm such as alterations in cardiac rhythm (tachycardia, bradicardia), of FCR variability (diminution until their loss or periodical variations of FCR in relation with the uterus contractions,) were seen in newborns [28].

Another study by Li et al concluded that hypothyroxinaemia, maternal subclinical hypothyroidism, with elevated TPOAb titres was associated with lower motor and intellectual development at 25-30 months [29].

Nazarpur et al reviewed the adverse effect of hypothyroidism, hyperthyroidism and thyroid autoimmune positivity on outcomes of pregnancy. Hyperthyroidism may cause stillbirth, miscarriage, preterm delivery, low birth weight, intrauterine growth retardation, preeclampsia and fetal thyroid dysfunction. Hypothyroidism may cause abortion, premature birth, low birth weight, intrauterine fetal death, increased rates of RDS and infant neuro developmental dysfunction. Few studies suggest that there may be higher risk of fetal distress, severe preeclampsia and neonatal distress in pregnant women with subclinical hypothyroidism [30].

Another systematic review by Hou et al assessed implications of maternal hypothyroidism on neonatal outcomes. After searching Pubmed, Embase and the Cochrane Controlled Trials Register databases, 9 trials were included in the analysis. Hypothyroidism was associated with increased risk of preterm birth and low birth weight. There was no increase in small for gestational age [31].

2.2.5. Polyhydramnios

Polyhydramnios is a condition where amniotic fluid level is more than normal. (AFI ≥25 cm, MVP ≥ 8 cm). This study reported 1.6% of polyhydramnios cases from total of 8798 deliveries.

More number of cesarean deliveries (43.1%), fetal distress (17.4% vs 6.9%) and NICU admission (17.4% vs 4.9%) were seen in the study [32].In another study, a significant linear association was found between AFI and Low birth weight (LBW), abruptio placentae, hypertensive disorders, preterm labor and macrosomia [33].Yefet et al showed new findings where Polyhydramnios was associated with congenital malformations (P = 0.016). Also, increased rate of cesarean section and birth weight> 90

^th

percentile was also seen. Among other main findings were genetic syndromes (P

= 0.043) and neurological disorders (P = 0.004) were other findings [34].

2.2.6. Hepatobiliary diseases

By a study conducted by Kawakita et al, it was seen that increasing total bile acid levels (TBA)

≥100 µmol/L were related with high risk of stillbirth. Also,TBA levels 40-49 µmol/L and TBA

≥mol/L would lead to meconium stained amniotic fluid [35].

17 Hepatobiliary diseases affecting are not much explored to see what effect they produce on outcomes of pregnancy. Some studies performed, show, there is some correlation between the two. In a study conducted by Alina et al, from a cohort of 2963 women, 247 women were found with liver diseases between 1996 to 2010 from Rochester epidemiology project database. Out of these, 134 women had pre- eclampsia, 72 were found with Hemolysis associated increased levels of liver enzymes and low platelet syndrome (HELLP), 26 had intrahepatic cholestasis of pregnancy and other complications like hyperemesis gravidarum , acute fatty liver disease of pregnancy. 70% of women with HELLP syndrome had preterm birth, 4% had abruptio placentae, 3% acute kidney injury and 3% infant death. Those with pre- eclampsia and liver disease together also showed 56% of preterm birth, 4%

abruptio, 3% of acute kidney injury, 0.7% of infant death [36].

2.3. Nutrition and Lifestyle

2.3.1. Nutrition

Poor maternal nutrition status is responsible for poor maternal and fetal outcomes. Multiple nutrient deficiencies may be responsible for complications in infants. The common adverse effects of poor nutrition on infants are low birth weight, preterm birth, and intrauterine growth retardation.

Nutrition deficiency is also associated with short- and long-term health problems such as neurologic disorders, learning disability, childhood psychiatric disorders, mental retardation, and chronic diseases in adult life [37].

Kathleen et al published a review on maternal nutritional requirements during pregnancy and impact of deficiency on infants. The most common adverse birth outcomes of poor nutrition are low birth weight, preterm birth, and IUGR which can have lifelong consequences for development, quality of life, and health care costs. Low birth weight may lead to 40%–80% of neonatal deaths, 98% of which occur in developing countries. Incidence of preterm birth, low birth weight, and IUGR are higher in developing countries than in developed countries and, within developed countries, are higher among low socioeconomic strata. They concluded that maternal nutrition is a modifiable risk factor and adverse birth outcomes can be prevented particularly among economically developing/low-income populations [38].

Akhter et al studied the effect of maternal iron deficiency anemia on cord blood iron status, placental weight and fetal outcomes. It was a cross sectional analytic study involving 50 hospitalized pregnant women and their neonates in Dhaka. Low maternal iron level was associated with low placental weight, low birth weight, APGAR score, gestational age and birth asphyxia [39].

Haider et al conducted a meta-analysis to study the associations of maternal anaemia and

prenatal iron intake with adverse pregnancy outcomes. The meta-analysis included 48 randomised

trials involving 17793 women and 44 cohort studies consisting of 1851682 women. Results of the

18 analysis suggested that anaemia during first or second trimester increases risk of low birth weight and preterm birth significantly. It also showed that supplementation of iron up to 66 mg/day improved birthweight and reduced risk of low birth weight [40].

Weinert et al assessed the effect of vitamin D deficiency in neonatal outcomes of pregnancies with gestational diabetes. The study included 184 pregnant women with gestational diabetes and had 25-hydroxyvitamin D < 20 ng/mL. Infants born to women with vitamin D deficiency had higher incidences of NICU admission, hypoglycemia, and were more frequently small for gestational age than infants born to women without vitamin D deficiency [41].

Wei et al conducted a systematic review and meta-analysis of observational studies reporting the link between maternal blood vitamin D levels and outcomes. They included 24 studies. Results indicated that pregnant women with circulating 25-hydroxyvitamin D level less than 50 nmol/l are at increased risk of preeclampsia, gestational diabetes, SGA and preterm birth [42].

Wang et al conducted a a large population-based birth cohort study to assess the link between maternal zinc level and the risks of low birth weight and small for gestational age infants. Out of 3187 pregnant women, serum zinc level was above normal in 2940 pregnant women (≥56 μg/dL) and 247 deficient (<56 μg/dL). Out of this, 7.3% of newborns with low birth weight and 15.0%

newborns with SGA were born to pregnant women with low zinc level. They concluded that maternal zinc deficiency during pregnancy elevates the risks of low birth weight and small for gestational age infants [43].

Finkelstein reviewed the role of vitamin B12 in perinatal health. Low Vitamin B12 levels (<148 pmol/L) during pregnancy may cause adverse maternal and neonatal outcomes. Vitamin B12 before and during pregnancy is important as it plays an important role in neural myelination, brain development, and growth. Infants born to vitamin B-12-deficient women may be at increased risk of neural tube closure defects. Impaired infant growth, psychomotor function, and brain development has been observed in infants born to vitamin B12 insufficient (<200 pmol/L) women [44].

Gernand et al reviewed impact of micronutrient deficiencies in pregnancy. Role of

micronutrients during different stages of pregnancy and impact of deficiency is given in the

Fig.2.3.1. Pregnant women in developing countries have deficiency of micronutrients as their diet is

not providing them. The most common nutrition deficiency conditions seen during pregnancy are

anemia (15–20%), Vitamin A deficiency (15%), zinc deficiency (15–74%), vitamin B12 deficiency

(19–74%), vitamin E (50–70%), and folate (0–26%). Micronutrient deficiencies might cause

preterm birth, death, impaired brain and cognitive development etc [45].

19 Fig. 2.3.1. Role of micronutrients at different stage of pregnancy and impact of deficiency (according to Gernand et al; 2016)

2.3.2. Prenatal Care

In one of the biggest study, Partridge et al performed a population-based cohort study using Birth and death infant data and fetal death data, from The Center for disease Control and prevention, for all deliveries in the US between 1995 and 2002. During the 8-year, 32206417 births occurred of which 28729765 (89.2%) were included in the analysis. Women ≤20 years, black non-Hispanic and Hispanic women, and those with less than high school education used inadequate prenatal care. It increased risk of prematurity, stillbirth, early neonatal dearth, late neonatal death, and infant death [46].

Abhishek Singh et al evaluated the association between antenatal care and neonatal mortality in

India. They used data from the District Level Household Survey 2007–8. At least four antenatal

visits to the hospital, consumption of 90 or more iron–folic acid tablets, and two or more tetanus

toxoid (TT) injections were used as criteria for antenatal care. Neonatal mortality was significantly

lower for infants of mothers who availed proper antenatal care. Risk of neonatal mortality was

significantly lower among women who received two or more tetanus injections but did not consume

20 90 or more iron folic acid tablets. Tetanus injection was the main determinant for reduction in infant mortality [47].

2.3.3. Smoking, Alcohol and Substance Abuse

Nicotine, alcohol, marijuana and cocaine are the common substance of abuse used during pregnancy. Maternal alcohol consumption has adverse effects on reproduction and fetal development. Arrays of adverse outcomes have been reported with heavy alcohol use and it includes risks of miscarriage, stillbirth and infant mortality, low birth weight, preterm delivery, small-for-gestational age and congenital abnormalities. Foetal alcohol spectrum disorder is another adverse outcome of prenatal alcohol exposure in infants [48]. Long-term impact of prenatal alcohol use includes cognitive and behavioural deficits, malformations, mental retardation, and psychosocial problems in childhood and adolescence.

Infants exposed to alcohol in utero are predisposed to infections because of disruption of the fetal immune system. This risk may be evident throughout the life. In utero exposure to alcohol is said to affect the immune system, indirectly, by increasing the risk of premature birth and directly by influencing immune mediated defenses, mainly in the lungs [49]. In utero exposure to alcohol increased the risk of infection by 2.5-fold and the risk further increased by 3-4 folds with excessive alcohol use during pregnancy [49]. Maternal alcohol exposure modulates the infant immunity by affecting the inflammatory environment within the newborn lung; decreasing in the fetal lung surfactant proteins; depleting antioxidant glutathione in the lung and inducing zinc deficiency [49].

Maternal alcohol consumption independently increases the risk of premature birth. It has been reported that there is 35-fold increase in the risk of delivering extremely premature infants (earlier than 32 weeks) following in utero exposure to heavy alcohol compared with women who did not drink during pregnancy [49]. Premature delivery due to in utero exposure to alcohol is mediated via a variety of factors, which include chorioamnionitis and placental abruption [49]. Despite withdrawal of alcohol from second semester, high level of alcohol intake, especially heavy and binge drinking patterns increases risk of preterm birth. High level consumption of alcohol increases the risk for small-for-gestational-age [51].

Maternal alcohol consumption of three drinks per week during the first trimester, increases the risk of spontaneous abortion (odds ratio (OR) of 2.3 [95% confidence interval (CI), 1.1-4.5]). The risk is higher with moderate alcohol consumption during first than in second trimester, and is even higher in the first 10 weeks (OR = 3.8; 95% CI,7-8.7) [52].

Maternal alcohol-use disorder is a significant risk factor for sudden infant death syndrome (SIDS) and infant mortality excluding SIDS. Maternal alcohol-use disorder is found to be responsible for at least 16.41% (95% CI, 9.73%–23.69%) of SIDS and 3.40% (95% CI, 2.28%–

4.67%) of infant deaths not classified as SIDS [53] compared to women who consumed <1

21 drink/week during pregnancy, the risk ratio for stillbirth a was 2.96 (95% CI, 1.37, 6.41) in women who consumed ≥5 drinks/week during pregnancy. Moreover, there is a higher rate of stillbirth due to fetoplacental dysfunction (1.37/1,000 births for women consuming <1 drink/week and 8.83/1,000 births for women consuming ≥5 drinks/week) [54]. It has also been reported that maternal consumption of ≥ 5 drinks/week increase the risk of stillbirth by 3-fold, even after adjustment for potentially confounding socioeconomic and lifestyle factors [55].

In contrast to smoking, maternal alcohol intake during periconceptional period increased the risk for d-transposition of the great arteries, neural tube defects, and multiple cleft palate in infants.

Maternal consumption of alcohol (<1 day/week) increased the risk for neural tube defects, and cleft palate and d-transposition of the great arteries by 1.6- to 2.1-folds.The risk was even higher more frequent consumption of alcohol by 2.1-fold for neural tube defects, and 2.6-fold for multiple cleft palate [56]. However, a meta-analysis did not find any significant association between maternal alcohol consumption and risk of congenital heart defects in offsprings [57].

Maternal consumption of alcohol affects the offspring in future and there are reports of hyperactivity and attention problems, learning and memory deficits, and problems with social and emotional development in the offsrings [58]. However, there is a lack of concrete evidence supporting the association between maternal alcohol consumption and cognitive or behavioural deficits in children in later ages. Heavy drinking (5 drinks/week) during pregnancy could be linked with increased risk of behavioural problems and cognitive deficits in offspring at age 3 years whereas light drinking does not [59]. A systematic review could not ascertain or refute an association between low to moderate alcohol consumption during pregnancy (up to 70 grams of alcohol per week) and speech and language outcomes in children [60].

Maternal smoking is associated with host of postnatal complications which include low birth weight, premature rupture of the membranes, placenta previa, placental abruption, and preterm birth. Maternal snuff use and smoking in pregnancy were associated with increased risks of extremely preterm birth. Maternal snuff use increased the risk of extremely preterm birth by twofold. The odds of very preterm birth among moderate smokers was 1.61; 95% CI: 1.39-1.87 (moderate smoking) and 1.91; 95% CI: 1.53-2.39 (heavy smoking) [61]. Maternal smoking also increases the risks of preterm birth due to preterm premature rupture of membranes and late pregnancy bleedings in a dose-dependent manner [62].

A systematic review of 173687 malformed cases and 11.7 million controls found a positive

association between maternal smoking and birth defects. The birth defects included

cardiovascular/heart defects, musculoskeletal defects, limb reduction defects, missing/extra digits,

clubfoot, craniosynostosis, facial defects, eye defects, orofacial clefts, gastrointestinal defects,

gastroschisis, anal atresia, hernia and undescended testes. Higher risk was observed for defects of

22 the cardiovascular, musculoskeletal and gastrointestinal systems, the face including orofacial clefts, and cryptorchidism. Lower risk for hypospadias and skin defects was observed among offspring of smokers while no association could be found for defects of the genitourinary, respiratory or central nervous systems [63].

Maternal snuff use or smoking in periconceptional period is associated with an increased risk of oral clefts. Compared with infants born to non-tobacco users, the adjusted odds ratios of any oral cleft for infants born to mothers who continued to use snuff was 1.48 (95% CI 1.00–2.21) and to smoke was 1.19 (1.01–1.41) [64].

Offsprings born to heroin-addicted women have increased risk of perinatal death, prematurity, fetal growth retardation, neonatal abstinence syndrome, and other perinatal complications.

Premature delivery was significantly more common among pregnant addicts. Risk of obstetric complications due to addiction could be attributed to high-risk lifestyle including poor nutritional habits, increased incidence of infectious and sexually transmitted diseases, other substance abuse, and poor antenatal care. Offsprings of addicted mothers are of lower birth weight and moreover there 7-fold risk of delivering small for gestational age (SGA) infants. There is 4-fold increase in the risk of various congenital anomalies in children born to addicted mothers [65].

2.3.4. Shift Work

Hormonal disturbance in women due to shift work might impair fetal growth or lead to complications of pregnancy. Shift work might lead to adverse pregnancy outcomes through disturbances of circadian rhythm and indirectly through psychosocial stresses and sleep disruption mechanisms. A review assessed the associations of shift work with preterm delivery, low birthweight, small for gestational age, and pre-eclampsia [66].They identified

• 17 studies assessing link between shift work and pre-term delivery

• 10 studies evaluated SGA and shift work

• 6 studies assessed LBW and shift work

• 4 studies investigated relationship between shift work and pre-eclampsia and/or gestational hypertension.

Shift work increased risk of preterm delivery in most of the studies, but relative risk was

significantly higher in two studies. Out of 10 studies analysing the risk between shift work and SGA

baby, 5 studies were prospective cohort investigations. A pooled risk estimate for SGA was

calculated as 1.12. Six studies analsysed risk of LBW baby among shift workers. One of the three

cohort studies showed a significantly elevated risk. Estimated combined risk was 1.27 when all the

study results were pooled. Link between pre-eclampsia was assessed in 2 studies and pregnancy-

induced hypertension in 2 studies but did not find any link. These results indicate that risk of PTD,

23

LBW, or SGA due to shift-work in pregnancy is small. These results are not compelling evidence

for mandatory restrictions on shift-working in pregnancy.

24

3 RESEARCH METHODS

3.1 Type of Research.

The present retrospective cross-sectional – case-control study was undertaken at the Department of Obstetrics and Gynecology at Kaunas Clinics, Kaunas, Lithuania. between July 2015 and January 2016 on women just after delivery. It is a quantitative study. Risk factors leading to various adverse outcomes were studied and explored. Also, adverse outcomes which were found out were categorized.

3.2 Research phenomenon or context

The outcomes of pregnancy which can occur to be adverse in nature, is a matter of concern. A healthy baby is what the parents and the Obstetrician want. Measures which can reduce the chances of such outcomes, become really important in such a situation. This research was carried out to explore the interdependency of probable risk factors, so that preventive strategies could be taken to avoid such consequences.

3.3 Theoretical Model

The risk factors of adverse neonatal outcome can be as simple as demographic factors (maternal age, body mass index (BMI), socioeconomic status and antenatal care), or complex factors like maternal diseases and nutritional status, or modifiable behavioral risk factors like smoking and alcohol intake. Studies conducted by Kahalil et al and Koo et al showed that there is association between advanced maternal age (AMA) and large for gestational age (LGA), small for gestational age (SGA), preterm delivery, low birth weight (LBW) [4,5]. Lower education especially among mothers, showed increased crude risk of preterm birth, SGA, stillbirth, neonatal and post neonatal death [11]. Women with diabetes show high risk of preterm birth, macrosomia, respiratory distress, heart malformations and cardiac trauma [17] while those with hypertension were linked to LBW, perinatal death, NICU admission [21]. Miscarriages, stillbirth, LBW, preterm birth, IUGR and pre- eclampsia were recorded in a study with cases of hyperthyroidism, while those with hypothyroidism, experienced abortion, premature birth, LBW, intrauterine death (IUD), Respiratory distress syndrome (RDS) and neurodevelopmental dysfunction [30]. Behavioral factors like heavy alcohol intake, could lead to miscarriage, stillbirth, infant mortality, LBW, preterm birth and SGA [48], while smoking, proved to be causing LBW, placental abruption, placenta previa, premature rupture of membranes and preterm birth [62].

3.4 Organization of research.

The bioethics committee and the Kaunas Clinics administration gave written permission to carry out the research. Since the research consisted of women after delivery, written permission from Head of the Department of Obstetrics and Gynecology was taken to carry out the survey in the department.

The research was started in July 2015, and the questionnaires were distributed twice a week in the

25 department, among women in postneonatal care after they had delivered the baby. A written consent was taken by women and it was assured to them that the information they provided would be used only for research purpose. The questionnaires were taken back the same day after they were filled.

The survey was carried out till January 2016. In total of 406 questionnaires were distributed and 349 questionnaires were returned. These 349 questionnaires were used to search for hospital records for mother's history and neonatal outcomes. Out of these, 39 women were excluded from study due to non availability of record, anonymity and incomplete information. 310 women finally formed the sample population for the research.

3.5 Research contingent

In Postneonatal care wards, 406 questionnaires were distributed to just delivered women and 349 filled questionnaires were returned back (response rate 86 %). Out of these, 39 questionnaires were excluded from the study. Final sample consisted of 310 women, out of which 122 women served as cases, while 188 were controls.

Cases were defined as women who showed any adverse outcome such as - stillbirth (infant who had died in the womb (>22weeks of pregnancy); preterm birth (those born before completing 37 weeks of pregnancy); low birth weight (LBW) (babies born less than 2500 gms); small for gestational age (SGA) (babies with birth weight <10th percentile for babies of same gestational age); large for gestational age (LGA) (babies with birth weight> 90 percentile for babies of same gestational age);

macrosomia (babies weighing > 4 kg at birth); dysplasia of fetus (ureterohydronephrosis, bilateral hydronephrosis, ventriculomegalia, multicystic dysplastic kidney, pielectasis) and infections.

Controls were defined as women who gave birth to alive and healthy neonates without adverse outcome.

3.6 Sample of research and its formation method

While planning the survey, the possible sample size was calculated. Knowing the population size of Kaunas (300000), confidence level 95%, margin of error taken (acceptable) 6% and response distribution 50%, it was calculated that 267 women must be surveyed.

The survey was carried out in Kaunas Clinics in the Department of Obstetrics and Gynecology, for 6 months from July 2015 to January 2016. All women who gave birth in this department were invited to participate in the survey. All the persons present in certain place at certain time were questioned, so the sample formed was a handy sample [67].

3.7 Research instruments and data sources:

The instruments which were used while performing the research were standardized questionnaire, case history and birth records of neonates.

1. Standardized questionnaire - the questionnaire distributed was in Lithuanian language. It

consisted of 52 questions (Annexure 2).

26 2. Case history and birth records - the hospital records from Obstetric and Gynecology Department 'Medicinos Dokumentų Išrašas' was used.(Annexure 3) Any pregnancy complications like anemia, hypertension, diabetes, other system dysfunctions were identified and adverse neonates outcomes as well as neonatal assessment was performed by birth records.

3. Birth weight percentile chart - Birth weight percentile chart (Annexure 4) was used to categorize babies as low birth weight (LBW), small for gestational age (SGA), large for gestational age (LGA), macrosomia, preterm birth (adverse outcomes) by referring to birth percentiles for that gestational age (for boys and girls).

3.8 Variables and their evaluation criteria

The questionnaire used consisted of four groups of variables - general information, socioeconomic situation, working conditions and lifestyle. The questionnaire also consisted of information about fathers of newborn. The variables in each section are-

i. General information - it included age of mother, number of consultations, weight , height, history of diabetes and hypertension, medications during pregnancy, hospital admissions (eg. Did you take any medication for hypertension before pregnancy?)

ii. Socioeconomic conditions - This section consisted of questions about marital status, education, profession, place of living and housing conditions. (eg. Where you lived during pregnancy?) iii. Working conditions - Questions about work such as work load, harmful factors at work, nature of

work, stress at home and work. (eg. Stress at home and work?)

iv. Lifestyle:- It covered information about smoking habits (number of cigarettes smoked, time spent in smoking environment, smoking at home), alcohol intake (number of times beer, wine and strong alcohol taken, amount of alcohol consumed), any drug intake. eg. (How often parents drank wine?)

3.9. Methods of data analysis:

Statistical analysis was performed using such programs as Statistical Package for Social Sciences (SPSS) version 20 and Excel. Also, birth weight percentile charts and International standard classification of Occupations (ISCO) were used.

Pearson Chi square test was used for testing differences in categorical variables and group variables were tested using Mann- Whitney U test. Means and standard deviations were also utilized to describe findings. P< 0.05 was considered significant.

1. Crosstabs - Crosstabs were used to see whether there is association between two variables and also the extent of association between the two variables. Here, bivariate relationship is being established between the cases and controls.

2. Leveny’s test for equality of variances (for testing homogeneity of variance assumption) -

Leveny’s test for equality of variance tests the difference in variance of the two groups, and since in

this study the variance of cases and controls was equal for parameters, t-test assumption was met.

27 3. T- test:- This test consists of variable and calculation of mean, standard deviation and standard error of mean between 2 groups. In this study, the purpose of using t-test was to test mean differences between cases and controls. (2 independent variables)

4. Cramer's V:- Cramer' V was calculated using chi-square statistics, as a measure of association between nominal variable (lifestyle and prenatal risk factors) and adverse neonatal outcome.

t-test for independent groups was applied to compare means of variables like gestational age, birth weight, length, APGAR score at 5 min of the two groups.

3 Group statistics: Provided mean and standard deviation for both groups and gives information that the sample size of 2 groups is similar.

3.10. Research ethics

The Bioethics Committee gave the permission to perform the research at the Kaunas Clinics. The

printed questionnaires were distributed and collected personally and the data was kept safe and not

shared.

28

4. RESULTS

4.1. Demographic characteristics of case and control groups

4.1.1 Age of respondents

The data was analyzed, to study the distribution of mothers, according to their age (Table 4.1.1.). It was seen that women who were 21- 34 years of age, formed the maximum percentage of the sample population. Around 1/4

^th

of the mothers belonged to advanced maternal age group (35 years and above), in both cases and controls. However, few mothers were less than 20 years of age.

There was no significant difference between the two groups due to age of mother (P>0.05).

Table 4.1.1. Distribution of mothers of neonates according to age

Variable

Cases N= 122

Controls

N= 184 P value

n % n %

Age (years)

<20 21-34

> 35

6 85 31

4.9 69.7 25.4

8 142

34

4.3 77.2 18.5

0.322

4.1.2 Education of parents of neonates

Table 4.1.2 shows, that among both mothers and fathers of the neonates, around half of the population had university education. Parents who were educated till secondary level came next.

However, no single category dominates the scene. A very small percentage was formed by parents who did not complete secondary education. When cases and controls are compared, it is seen that significant difference could not be established between two groups.

Table 4.1.2. Distribution of mothers and fathers of neonates according to level of education

Education level

Mothers

P value

Fathers

P value Cases (M)

N= 120

Controls (M) N= 180

Cases (F) N= 116

Controls (F) N= 175

n % n % n % n %

Incomplete Secondary

College Bachelor's

Master's

2 46

9 29 34

1.7 38 7.4 24 28.1

4 51 14 54 57

2.2 28.3

7.8 30 31.7

0.6 0.1 0.8 0.2 0.7

4 42 15 36 19

3.4 36.2 12.9 31 16.4

9 63 25 44 34

5.1 36 14.3 25.1 19.4

0.6 0.9 0.8 0.09

0.2