Maternal risk factors for low birth weight neonates: A hospital based case-control study in rural area of Western Maharashtra, India

Abstract

Low birth weight (LBW) is a major determinant of infant mortality and morbidity. It is generally recognized that the etiology of LBW is multifactorial. Present case control study was conducted with the objective of studying maternal risk factors associated with full term LBW neonates. A total of 200 cases and 200 controls of age 18–35 years who delivered a live-born singleton baby were enrolled. The data information was gathered from the maternal health records and interviewing the mothers of these neonates. All the data were entered into the SPSS package (version 17). Association of the risk factors under study was assessed by applying chi –square test. To assess the strength of association the odds ratio and 95% confidence interval of odds ratio was calculated. Majority of the cases and controls belongs to 20-29 years age group. The proportion of low income, illiterate/primary educated, farm labourer mothers, primiparas, and women with Spacing < 2 years were higher among the LBW newborns. LBW was strongly associated with anaemia [χ2=17.33, p<0.0001]. Significant risk factors identified in univariate analysis included pregnancy-induced hypertension [OR=4.09(1.49-11.19)], pre pregnancy maternal weight <45 kgs [OR=4.41(2.30-8.46)], maternal height <145 cms [OR=2.34(1.17-4.66)] and Inadequate antenatal care (χ2=24.81, p<0.0001). Large number of mothers from rural area were not utilizing or inadequately utilizing antenatal care services. Many risks for LBW can be identified before pregnancy occurs. Health education, socio-economic development, maternal nutrition, and increasing the use of health services during pregnancy, are all important for reducing LBW.

Full text

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National Journal of Community Medicine Vol 2 Issue 3 Oct-Dec 2011 Page 394
ORIGINAL ARTICLE .
MATERNAL RISK FACTORS FOR LOW BIRTH WEIGHT
NEONATES: A HOSPITAL BASED CASE-CONTROL
STUDY IN RURAL AREA OF WESTERN MAHARASHTRA,
INDIA
Deshpande Jayant D1, Phalke DB2, Bangal V B3, D Peeyuusha4, Bhatt Sushen4
1Associate Professor 2Professor and Head, Department of Community Medicine, 3Professor and Head,
Department of Obstetrics & Gynecology, 4Third M.B.B.S. Student, Department of Community
Medicine, Rural Medical College, Pravara Institute of Medical Sciences, Loni, Maharashtra, India
Correspondence:
Deshpande Jayant D.
Associate Professor, Department of Community Medicine(P.S.M.)
Rural Medical College, Pravara Institute of Medical Sciences,
Loni, Maharashtra, India
E-mail: drjayant10@gmail.com Mobile: 9762601050
ABSTRACT
Low birth weight (LBW) is a major determinant of infant mortality and morbidity. It is generally
recognized that the etiology of LBW is multifactorial. Present case control study was conducted with
the objective of studying maternal risk factors associated with full term LBW neonates. A total of 200
cases and 200 controls of age 18–35 years who delivered a live-born singleton baby were enrolled. The
data information was gathered from the maternal health records and interviewing the mothers of
these neonates. All the data were entered into the SPSS package (version 17). Association of the risk
factors under study was assessed by applying chi –square test. To assess the strength of association
the odds ratio and 95% confidence interval of odds ratio was calculated. Majority of the cases and
controls belongs to 20-29 years age group. The proportion of low income, illiterate/primary educated,
farm labourer mothers, primiparas, and women with Spacing < 2 years were higher among the LBW
newborns. LBW was strongly associated with anaemia [χ2=17.33, p<0.0001]. Significant risk factors
identified in univariate analysis included pregnancy-induced hypertension [OR=4.09(1.49-11.19)], pre
pregnancy maternal weight <45 kgs [OR=4.41(2.30-8.46)], maternal height <145 cms [OR=2.34(1.17-
4.66)] and Inadequate antenatal care (χ2=24.81, p<0.0001). Large number of mothers from rural area
were not utilizing or inadequately utilizing antenatal care services. Many risks for LBW can be
identified before pregnancy occurs. Health education, socio-economic development, maternal
nutrition, and increasing the use of health services during pregnancy, are all important for reducing
LBW.
Key words: Low birth weight, risk factors, case control study
INTRODUCTION
Low birth weight (LBW) is an important
indicator of reproductive health and general
health status of population. LBW is considered
the single most important predictor of infant
mortality, especially of deaths within the first
month of life. 1 It continues to remain a major
public health problem worldwide especially in
the developing countries. The prevalence of low
birth weight in India was found to be 26%. As
per the WHO estimation about 25 million low
birth weight babies are born each year, nearly
95% of them in developing countries. 2
Across
the world, neonatal mortality is 20 times more
likely for LBW babies compared to heavier
babies (≤ 2.5 kg). 3, 4 LBW is a result of preterm
birth, intrauterine growth restriction, or a

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combination of both pathophysiologic
conditions. There are numerous factors
contributing to LBW both maternal and fetal.
Weight at birth is directly influenced by general
level of health status of the mother. Maternal
environment is the most important determinant
of birth weight, and factors that prevent normal
circulation across the placenta cause poor
nutrient and oxygen supply to the fetus,
restricting growth. The maternal risk factors are
biologically and socially interrelated; most are,
however, modifiable. Krammer has identified 43
potential factors for low birth weight.4 Not that
all the factors, should be present in a given area.
The factors vary from one area to another,
depending upon geographic, socioeconomic and
cultural factors. The mortality of low birth
weight can be reduced if the maternal risk
factors are detected early and managed by
simple techniques. Thus it is necessary to
identify factors prevailing in a particular area
responsible for low birth weight. With this
background in mind the objective of the present
study was to identify the maternal risk factors
associated with LBW in rural area of western
Maharashtra.
MATERIAL AND METHOD
Present case control study was conducted in a
tertiary care teaching hospital in rural area of
western Maharashtra. The study data were
collected between March 2010-August 2010 by
interviews with the mothers, abstraction of
medical records and anthropometry. The World
Health Organization (WHO) definition of LBW
was used, i.e., birth weight less than 2500g. 5
Eligibility criteria for cases were: to deliver a live
newborn weighing less than 2,500 g. To be
eligible as a control, mothers should have
delivered a single newborn weighing more than
2,499g. Mother of babies with birth weights of >
2,499 g who were born consecutively after each
case, constituted the control group. Controls
were identified from birth records as the next
eligible delivery of a non-LBW baby after a
woman delivered an LBW baby. A total of 200
cases (vaginal delivery or caesarean section) and
200 controls of age 18–35 years who delivered a
live-born singleton baby through without
congenital malformation and with gestational
age 37–42 weeks were enrolled within one day
of delivery. Mothers who had multiple births
were excluded. All babies were weighed within
one hour after birth. The data were entered into
a standardized questionnaire after verbal
consent was obtained form the mother. The data
information was gathered from the maternal
health records and interviewing the mothers of
these infants.
Study variables: Study variables were maternal
age, height, pre-pregnancy weight, education,
occupation, socioeconomic status, type of
family, parity, interval between birth of the
newborn baby and the previous delivery,
Antenatal care (ANC) during current
pregnancy, iron and folic acid tablets consumed
and strenuous physical activity during
pregnancy. History was asked regarding
consumption of tobacco in any form regularly.
History of abortion was classified as ever/never
had abortion. Birth interval between the current
and last pregnancy was taken as a continuous
variable. Total numbers of ANC visits for the
current pregnancy were categorized as ≥ 4 visits
and < 4 visits, based on the WHO and United
Nations International Children's Emergency
Fund (UNICEF) criteria that women should
have ≥ 4 ANC visits with an appropriate health
care provider . Adequate antenatal care was
considered when the pregnant women was
registered at any time, had at least four
antenatal checkups, had adequately vaccinated
against tetanus, had consumed at least 100
tablets of iron and folic acid. Gestational age
was calculated from the first day of the last
menstrual period reported by the mother. 6
Illness developed during pregnancy was also
recorded; these include pregnancy-induced
hypertension (PIH), eclampsia / preeclampsia,
Rhesus problem, infections and others. Baby
characteristics included sex and the birth
weight. Physical examination was undertaken
after the interview was over. The available
health records were also reviewed. The
investigations such as haemoglobin, Blood
group, VDRL and urine sugar and albumin were
recorded from the case sheets. Socioeconomic
status as suggested by B.G.Prasad was adopted
and modified as per all India consumer price
index. 7
Statistical analysis: All the data were entered
into the SPSS package (version 17). Association
of the risk factors under study was assessed by
applying chi –square test taking a level of
significance of P < 0.05. To assess the strength of
association the odds ratio and 95% confidence
interval of odds ratio (O.R.) was calculated.

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RESULTS
The main maternal characteristics of the study
population are shown in Table 1. The mean age
of mothers in case group was 22.7±2.92 and in
control group 22.28±2.74. Majority of the cases
and controls belongs to 20-29 years age group.
Table 1: Comparison of basic variables of mothers between cases and controls
Variable Cases Control
Mean age (years) 22.7 ± 2.92 22.28 ±2.74
Height (cm) 152.06±6.26 153.62±5.31
Pre-pregnancy weight (kg) 48.58±7.91 52.35±6.3
Mean weight gain in pregnancy (kg) 4.9±1.2 6.9±1.5
Birth spacing (months) 22.3±5.1 30.2±6.2
Mean weight of newborn(gram) 1864.97±465.06 2848.35±298.53
The mean birth weight in LBW group babies
was 1864.97±465.06 g and in the control group
was 2848.355±298.53 g. Table 2 shows the
distribution of various factors among cases and
controls.
Table 2: Maternal risk factors for low birth weight
Variable Cases (%)
(n=200)
Control (%)
(n=200)
Odds ratio
(95% CI)
p value
Age(years) <20/>30 years 31(15.5) 19(9.5) 1.74(0.95-3.91) 0.09
Height <145cm 28(14) 13(6.5) 2.34(1.17-4.66) 0.021
Lower socio-economic status (Class IV+V) 54(27) 36(18) 1.68(1.04-2.71) 0.04
Maternal occupation farm labourer 49(24.5) 19(9.5) 3.09(1.74-5.47) 0.0001
Maternal education-illiterate/primary 71(35.5) 49(24.5) 1.69(1.1-2.61) 0.02
Nuclear family 103(51.5) 97(48.5) 1.12(0.76-1.66) 0.61
Pre pregnancy weight< 45 kg 47(23.5) 13(6.5) 4.41(2.30-8.46) <0.0001
Spacing < 2years 111(55.5) 83(42.5) 1.75(1.18-2.61) 0.006
Primigravida 71(35.5) 55(27.5) 1.45(0.94-2.21) 0.1064
No ANC registration/late ANC registration 83(41.5) 49(24.5) 2.18(1.42-3.35) 0.0004
Inadequate ANC 107(53.5) 57(28.5) 2.88(1.90-4.36) <0.0001
Bad obstetrics history 33(16.5) 18(9) 1.99(1.08-3.68) 0.03
Maternal Infections 9(4.5) 7(3.5) 1.29(0.47-3.5) 0.79
History of infertility 11(5.5) 9(4.5) 1.23(0.50-3.05) 0.8185
Tobacco consumption 23(11.5) 4(2) 6.36(2.15-18.77) 0.0003
Heavy physical activity 15(7.5) 5(2.5) 3.16(1.12-8.87) 0.03
PIH 19(9.5) 5(2.5) 4.09(1.49-11.19) 0.0062
Anaemia 85(42.5) 45(22.5) 2.54(1.64-3.93) <0.0001
Caesarean section delivery 59(29.5) 61(30.5) 0.95(0.61-1.46) 0.91
The proportion of low income,
illiterate/primary educated and farm labourer
mothers were significantly higher among the
LBW newborns. Amongst the LBW there were
greater proportion of primiparas, mothers below
the age of 20 years and women with Spacing < 2
years. The ANC experience of the mothers in the
control group was significantly better than that
of cases. LBW was strongly associated with
inadequate antenatal care. [χ2=24.81, p<0.0001].
The haemoglobin status and daily intake of iron
supplements was better among the control
group. Mothers who had bad obstetric history
showed poor outcome in their present
pregnancy also. A significant association was
found between bad obstetric history and birth
weight of baby. Anaemia, nonpregnant weight
below 45 kg, height less than 145 cm was
significantly more common amongst the
mothers of LBW babies. A significantly higher
proportion of mothers of LBW neonates had PIH
and eclampsia during the current pregnancy
than controls [O.R. = 4.09 (1.49-11.19)].
Furthermore, a significantly higher proportion
of mothers of LBW infants were having history

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of tobacco consumption than controls
(p=0.0003).
DISCUSSION
Factors associated with low birth weight, often
termed as ‘‘risk factors'' and their presence in an
individual woman indicates an increased
chance, or risk, of bearing a low birth weight
infant. Globally, LBW as indicator is a good
summary measure of a multifaceted public
health problem that includes long-term maternal
malnutrition, ill health, hard work and poor
pregnancy health care.
In present case control study from rural area,
lower socioeconomic status, maternal education,
maternal occupation farm labourer and having
heavy physical activity during antenatal period
were significantly associated with low birth
weight. However maternal age, having nuclear
family and parity has not identified as
significant risk factors for LBW babies. Krammer
4, Hirve and Ganatra 8 Deshmukh et al 9
also
found significant association between
socioeconomic status and birth weight of baby.
The percentage of illiterate and primary
education was more in cases (35.5%) as
compared to control group (24.5%). Hirve and
Ganatra 8 found that the adjusted odds ratio for
delivering LBW decreases significantly with
increasing education status of the mother. In
rural area women from lower socioeconomic
status often continue strenuous physical work
through pregnancy. In our study, maternal age
had no significant association with LBW. Our
findings on maternal age as a risk factor is
consistent with studies conducted by
Mavalankar et al10 in India and Fikree et al 11 in
Pakistan. Anand and Garg 12 also found no
significant relationship between maternal age
and LBW. Proportion of primigravida was high
among cases as compared to control but the
difference was not statistically significant. In
contrast, previous studies have revealed that
primiparity is significantly associated with
LBW. 9, 13
This study has shown that low birth weight was
significantly associated with inadequate
antenatal care, pre-delivery weight ≤45 kg,
height ≤145 cm, bad obstetrics history, tobacco
consumption, PIH and anemia. These findings
are consistent with Kramer's meta-analysis. 4
Malik et al 14 found a strong correlation between
birth weight and maternal height. Maternal
height < 145 cm contributed significantly to a
high rate of L.B.W. Effects of pre pregnancy
maternal weight; bad obstetrics history
(previous abortions) and anaemia were
consistent with another study in Ahmadabad. 10
In a hospital-based study in Calcutta Pahari et al
15 reported abortion as one of the main-causes of
adverse pregnancy outcomes in addition to
anaemia and hypertensive disorder. Anemia
was one of the common problems in the present
study from rural area. Almost 42.5% of mothers
who delivered LBW babies were anaemic.
Deshmukh et al 9 also found that anaemia was
significantly associated with LBW. Similarly,
Mavlankar et al 10 observed that pre pregnancy
maternal weight, and anaemia was important
determinant of low birth weight. The association
of tobacco consumption with low birth weight
observed in this study has also been reported by
Deshmukh et al. 9 and Gupta et al. 16 Antenatal
care had a strong influence on birth weight. In
present study it was found that most of mothers
from rural area start attending ANC clinics in
their sixth to seventh months of gestation.
Deswal et al 17 also reported that low maternal
weight, under nutrition, lack of antenatal care,
short inter-pregnancy interval, toxemia of
pregnancy were independent factors increasing
the risk of low birth weight significantly. Rural
women from lower socio-economic status are
more susceptible to poor diet and infection and
more likely to undertake physically demanding
work during pregnancy. Large number of
mothers from rural area are not utilizing or
inadequately utilizing antenatal care services.
Antenatal care for pregnant mothers is an
established factor to improve pregnancy
outcome, appropriate nutritional education and
food supplements must be given to the mothers
with poor weight gain. Access to quality
antenatal care should be viewed as potentially
important since it also offers opportunities for
counseling and risk detection apart from its
necessity for maternal health. It is generally
recognized that the etiology of LBW is
multifactorial. Special attention of health care
professionals is necessary for identification of
these risk factors for low birth weight. Various
factors are clearly and consistently linked to low
birth weight. Numerous opportunities exist
before pregnancy to reduce the incidence of low
birth weight, yet these are often overlooked in
favor of interventions during pregnancy.
CONCLUSION

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National Journal of Community Medicine Vol 2 Issue 3 Oct-Dec 2011 Page 398
Many risks for LBW can be identified before
pregnancy occurs. Health education, socio-
economic development, maternal nutrition, and
increasing the use of health services during
pregnancy, are all important for reducing LBW.
Acknowledgement: We acknowledge the
cooperation extended by Management of
Pravara Medical Trust, Principal and
Department of Obstetrics and Gynecology Rural
Medical College, Loni.
REFERENCES
1. Ryan CA, Ryan F, Keane E, Hegarty H. Trend analysis
and socio-economic differentials in infant mortality in
the Southern Health Board, Ireland. Ir Med J 2000;
93:204-6.
2. Park K. Park’s Text book of preventive and social
medicine. 18th Edition. Jabalpur: M/s Banarsidas
Bhanot, 2005: 395-396.
3. UNICEF: Low Birth Weight, Country Regional and
Global estimates.
[http://www.unicef.org/publications/index_24840.htm
l]. Accessed August12, 2011
4. Kramer MS. Determinant of low birth weight:
Methodological assessment and Meta analysis. Bull
WHO 1987; 65(5): 663-737.
5. World Health Organization. International Classification
of Diseases, Ninth revision,Vol. 1 Geneva, World
Health Organization, 1977.
6. Smith GC, Pell JP, Dobbie R: Caesarean section and risk
of unexplained stillbirth in subsequent pregnancy.
Lancet 2003, 362(9398):1779-1784
7. Kumar P. Social classification – Need for constant
updating. Indian J Commun Med 1993; 18:60-61.
8. Hirve SS, Ganatra BR. Determinants of low birth
weight: a community based prospective cohort study.
Indian Pediatr 1994; 31:1221-5.
9. Deshmukh JS, Motghare DD, Zodpey SP, Wadhva SK.
Low birth weight and associated maternal factors in an
urban area. Indian Pediatr. 1998; 35:33-6
10. Mavlankar DV, Gray Ronald H, Trivedi CR. Risk
factors for preterm and term low birth weight in
Ahmedabad, India. Int J Epidemiol 1992; 21:263-72.
11. Fikree FF, Berenes HW. Risk factors for term
intrauterine growth retardation Community based
study in Karachi. Bull WHO 1994; 72:581-87.
12. Anand K,Garg BS. A study of factors affecting low birth
weight. Ind j com med 2000;25:57-62
13. Nurul A, Abel R, Sampathkumar V. Maternal risk
factors associated with low birth weight. Indian J
Pediatr 1993; 60:269-274.
14. Malik S,Ghidiyal RG,Udani R, Waingankar R. Maternal
Biosocial factors affecting low birth weight.Indian
Journal of Paediatrics 1994;33:1222-25
15. Pahari K, Ghosh A: Study of pregnancy outcome over a
period of five years in a postgraduate institute of west
Bengal. J Indian Med Assoc 1997; 95:172-4.
16. Gupta PC, Sreevidya S. Smokeless tobacco use, birth
weight, and gestational age: population based
prospective cohort study of 1217 women in Mumbai,
India. BMJ. 2004; 328:1538.
17. Deswal BS, Singh JV, Kumar D. A Study of Risk Factors
for Low Birth Weight. Indian J Community Med.1999
;24 : 127-131.