Maternal risk factors associated
with intrauterine growth restriction: hospital based study
Ashwani N 1, Neela Aruna
Rekha 2, Babu M.S.3, C. Suresh Kumar 4, O. Tejo Pratap 5
1Dr. Neetika Ashwani, Medical Officer, Special newborn care unit
(SNCU), 2Dr. Neela Aruna Rekha, Assistant Professor, Gynaecology and
Obstetrics, 3Dr. Mendu Suresh Babu, Assistant Professor, Department of
Paediatrics, 4Dr. C. Suresh Kumar, HOD and Professor of Neonatology,
all authors are affiliated with Niloufer Hospital, Osmania Medical
College, Hyderabad, 5Dr. O. Tejo Pratap, Neonatologist, Department of
Neonatology, Fernandez Hospital, Hyderguda, Hyderabad, India
Address for
correspondence: Dr. Neetika Ashwani, Email:
cuteniti_19@yahoo.com
Abstract
Objective:
To study the maternal risk factors of intrauterine growth restriction. Methods: A
retrospective analysis was done at a tertiary care Hospital. Ninety
three inborn intrauterine growth restriction cases were selected and
data was collected by perusal of antenatal records. Intrauterine growth
restriction was defined as occurring if birth weight of the newborn is
below 10th percentile for gestational age on the intrauterine growth
curve based on Fenton’s charts. Results: Mean age of
the mothers included in the study was 20.2 ± 2.857 years.
Forty four (47.3%) were born to primipara and 49 (52.7%) to
multigravida. Younger maternal age, multiparity were found to be the
significant socio-demographic factors associated with Intrauterine
growth restriction while, pre eclampsia, chronic hypertension and
anemia were the maternal biological factors found to be significantly
associated on bivariate analysis. Conclusions:
Younger age, multigravida and chronic medical illnesses are the main
risk factors in this hospital based population. Inclusion of prenatal
education and screening for medical disorders in antenatal care
guidelines will help in curtailing the incidence of IUGR.
Keywords:
maternal factors, IUGR, tertiary centre
Manuscript received:
14th September 2016,
Reviewed: 25th September 2016
Author Corrected:
7th October 2016,
Accepted for Publication: 19th October 2016
Introduction
Linear growth failure is caused by multiple factors including parental
factors. Infants with intrauterine growth restriction (IUGR) are
defined as those with birth weight below the 10th percentile for its
gestational age and it is a consequence of several factors [1]. Genetic
and environmental factors influence the development throughout the
growth period. Linear growth failure is largely confined to the
intrauterine period and the first few years of life, and it is caused
by multiple factors like inadequate diets, infections, maternal chronic
diseases etc. [2,3].
IUGR is observed in about 24% of newborns; approximately 30 million
infants suffer from IUGR every year [4]. The burden of IUGR is
concentrated mainly in developing countries, especially in Asia which
accounts for nearly 75% of all affected infants. In India, the
prevalence of LBW has been reported as 26% [5] while the proportion of
IUGR has been found to be 54% [6,7]. The neonatal mortality rate of a
small for gestational age infant born at 38 weeks is 1% compared to
0.2% in those appropriate for gestational age [8].
The common risk factors include maternal causes (hypertension,
diabetes, cardiopulmonary disease, anemia, malnutrition, smoking, drug
use), fetal causes (genetic disease including aneuploidy, congenital
malformations, fetal infection, multiple pregnancies), and placental
causes (placental insufficiency, placental infarction, placental
mosaicism). The risk factors for IUGR different in our region compared
to developed region. IUGR increases the risk for intrapartum asphyxia,
preterm delivery, and risks associated with preterm delivery, including
but not limited to respiratory distress syndrome, sepsis, seizures,
intraventricular hemorrhage, and necrotizing enterocolitis [9,10].
Other neonatal morbidities include polycythemia, hyperbilirubinemia,
hypoglycemia, and hypothermia. Effects of IUGR often affect childhood
and adult life, as well. During the childhood period, associations are
noted for increased risk of cerebral palsy, growth delay, short
stature, and neurodevelopmental impairment [9,11]. In adult life,
individuals who had IUGR were noted to have higher incidence of
hypertension, diabetes, obesity, coronary artery disease, stroke, and
metabolic syndrome [12].
However in developing countries evidence on the association between
these factors and IUGR is scarce. Hence we tried to elucidate some of
the major risk factors for intrauterine growth restriction in south
India.
Materials
and Methods
A retrospective descriptive analysis was undertaken at a tertiary care
hospital, Niloufer Hospital, Hyderabad, India to study the maternal
determinants of intrauterine growth restriction.
Retrospectively babies born in the 8 months period from October 2015 to
May 2016 were included in the study. We included infants born to
singleton mothers with birth weight below 10th centile on Fenton charts
in our hospital. We excluded infants with major malformations.
Antenatal records of mothers were scrutinized for maternal and
obstetric factors, which included age, parity, maternal weight,
hemoglobin level, spacing between present and past pregnancy, pregnancy
induced hypertension, antenatal visits and h/o abortion/stillbirth, any
illness and treatment received during pregnancy and record of
hospitalization during present pregnancy. Weight of the newborns was
obtained from case records. In our hospital, baby is weighed
immediately after birth and information is noted on the mothers` case
sheet. Data was analyzed using R programming software version 3.0. For
descriptive statistics frequencies were tabulated and chi square test
was done to see significance between the groups. A
‘P’ value <0.05 was considered statistically
significant.
Results
A total of 4315 babies were delivered in our center during the study
period, of which 93 (2.15%) with mean birth weight of
1.93±0.36 kg (range 0.89-2.3kg) and mean gestation age of
38.19±1.75 weeks (range 32-41weeks) were diagnosed as IUGR.
Forty four were born to primipara (47.3%) and 49 (52.7%) to
multigravida. Fifty eight (62.4%) were females and 35 (37.6%) were
males. Forty three (46.2%) mothers were at young age (<20yrs)
and eight (8.6%) mothers with weight <45kg. Birth spacing less
than 1 year were found in 13(14%) women and 22(23.7%) women were found
to have birth spacing between 1-2 years.
The etiological factors are shown in table 1.
Table 1: Perinatal risk
factors
|
SGA # |
OVERALL # |
p value |
| Anemia |
10.8 |
1.96 |
<0.001 |
| Hypertension |
10.8 |
2.94 |
<0.001 |
| Pre eclampsia |
16.1 |
5.02 |
<0.001 |
| Eclampsia |
1.1 |
0.50 |
0.957 |
| Diabetes mellitus |
1.1 |
0.60 |
0.999 |
| APH* |
8.6 |
1.04 |
<0.001 |
| Infections |
1.1 |
0.69 |
0.999 |
| Hypothyroid |
4.3 |
4.77 |
0.999 |
| No med comp** |
46.2 |
|
|
Pre eclampsia was considered as one of the important risk factors of
IUGR babies followed by anemia, hypertension and antepartum hemorrhage.
The other perinatal risk factors did not reach statistical
significance.
In forty three (46.2%) babies, no medical cause was found for SGA
babies. Hence we analyzed socio-demographic factors for these SGA
babies (table 2).
Table 2:
Socio-demographic factors with no medical complications
|
|
Frequency(n=43)
|
Percentage (%)
|
|
young maternal age
|
17
|
39.5
|
|
low maternal weight
|
3
|
7.0
|
|
Multigravida
|
10
|
23.3
|
|
short stature
|
1
|
2.3
|
|
Undetermined
|
12
|
27.9
|
Young maternal age had high prevalence (39.5%) for SGA
babies followed by multigravida (23.3%), low maternal weight (7.0%) and
short stature (2.3%).
Twelve (27.9%) babies born to primi mothers had no cause determined. Of
12 babies 7 were associated with oligohydramnios.
Discussion
The ability to reach an optimal birth weight, results from the
interaction between the fetal growth potential and the environment. The
fetus requires several substrates for normal growth, the most important
being oxygen, glucose and amino acids. Any persistent decrease in the
availability of any of these substrates will limit the ability of the
fetus to reach its growth potential. The availability of substrates
necessary for fetal growth may be limited by pathological conditions
affecting the mother, the placenta and the fetus [13].
IUGR is a multifactorial phenomenon. Many of these factors are
inter-related and they can confound the results in addition to
modifying the independent estimates of relative risk associated with a
risk factor [14]. The perinatal risk factors responsible for IUGR in
developing countries differ from the western world. Unlike our country
the common risk factors related to IUGR in western countries is smoking.
In this retrospective study, we described risk factors for severe IUGR.
Obstetric and maternal risk factors for IUGR are well described in many
studies and the present cohort is comparable to cohorts described in
other studies.
Our study demonstrated that pre eclampsia, hypertension, and anemia
were the main maternal biological factors associated with IUGR which
was comparable with other studies [13]. Anemia is a common problem in
developing countries in pregnant women and increases the incidence of
LBW and IUGR [15,16].
Maternal age and parity were found to be the significant maternal
socio-demographic determinants of intrauterine growth restriction in
the present study. Teenage mothers (age less than 20 years) are well
known for adverse pregnancy outcomes. However, in this study teenage
mothers were independently associated with IUGR compared to middle and
older age mothers which are comparable to other studies [17-19]. This
result is in contrast to other studies in India. Instead of teenage
mothers, studies in India associated maternal weight and primiparity
[15,16].
Kramer’s meta-analysis [20], and other studies conducted in
developing countries have identified maternal weight (<45kg),
maternal height (<145cm) as potential risk factors for LBW
babies. Low socioeconomic status and low educational status leads to
low health consciousness, lower nutritional status and low antenatal
attendance, leading to the increased risk of IUGR babies [21]. A short
interpregnancy interval is associated with IUGR [22]. In the present
study, previous history of abortion/stillbirth, spacing, maternal
weight, and antenatal visits were not found to be significant. Another
study done in India showed that toxemia of pregnancy (30.09%),
hypertensive diseases of pregnancy (HDP) excluding toxemia (5.8%),
diabetes mellitus (1.94%), medical disorders including renal and
cardiac (3.88%), anemia and Intra Uterine infection (0.97%) were the
main conditions responsible for LBW and in 56.3% pregnancies, no cause
could be ascertained [13]. But our study showed that 16.1% mothers
suffered from pre eclampsia, 10.8% of the mothers with IUGR were
anaemic and 46.2% of them were young maternal age. Around 10.8% of the
mothers with IUGR babies suffered from hypertension.
We found 12 cases (27.9%) had no cause determined. Of late genetic
factors affecting the mother, placental and fetus are increasingly
reported. Genetic causes can contribute to 5-20 % of IUGR, especially
for early onset growth restricted fetuses. Monitoring of weight gain on
prenatal visit can identify the maternal nutrition. Also, measurement
of the symphysis-fundal height (SFH) height provides a helpful measure
to assess fetal growth during office visits.
The women at risk for IUGR can be assessed with uterine artery Doppler
to further evaluate the initiation of baby ASA before 16 weeks
gestation. Diagnosis of IUGR is made by when the ultrasound EFW is less
than 10th percentile. The umbilical artery Doppler should be performed
in IUGR fetuses to formulate the antenatal management plans. Invasive
testing should be offered to rule out aneuploidy and in utero fetal
infection. Serial growth ultrasound and UA Doppler studies are used to
follow-up the fetus (es) with IUGR. As the IUGR foetuses have fivefold
increase in the stillbirth rate as well as threefold increase in
neonatal mortality and morbidity, a very close monitoring of the labour
is warranted. As the chance of IUGR babies in subsequent pregnancies is
higher, these patients should be followed up post-nataly.
This study provides baseline information from a tertiary hospital in
this region, which could help with possible intervention regarding
maternal and newborn health in the future. We could not take more
information on certain risk factors like weight gain during pregnancy
because of lack of available data from the records. We recommend the
health authorities to strengthen the maternal health programmes
focusing on maternal nutrition and iron and folic acid supplementation
during antenatal period. The strategy also needs to focus attention on
nutrition education to facilitate better weight gain during adolescent
period. Discouraging teenage pregnancy is also essential in order to
reduce the burden of LBW/IUGR babies.
Thus findings of this study emphasizes the need for improving the
quality and utilization of antenatal care, nutritional education to
improve the weight gain during pregnancy, spacing, and prevention and
proper management of risk factors like anemia and hypertension. The
researchers concluded that there is a need to control risk factors to
reduce the incidence and prevalence of Intra uterine growth
restriction.
Conclusions
IUGR newborns are common in the developing countries. So in conclusion,
comprehensive approaches which institute a combination of interventions
to improve the overall health of the women are needed. Such approaches
are likely to be most effective in reducing the IUGR problem in India.
As IUGR infants can have long term morbidities, authorities should
concentrate on measures to reduce this problem.
Acknowledgement- We
thank Dr. Raja Sriswan Mamidi, Scientist B, National Institute of
Nutrition, Hyderabad for assistance with statistical analysis and for
comments that greatly improved the manuscript.
Funding:
Nil, Conflict of
interest: None initiated.
Permission from IRB:
Yes
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How to cite this article?
Ashwani N, Neela Aruna Rekha, Babu M.S, C. Suresh Kumar, O. Tejo
Pratap. Maternal risk factors associated with intrauterine growth
restriction: hospital based study. Int J Med Res Rev
2016;4(12):2125-2129.doi:10.17511/ijmrr.2016.i12.08.