maternal short stature a risk factor for low birth weight in neonates

7/27/2019 Maternal Short Stature a Risk Factor for Low Birth Weight in Neonates

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J M e d A l l i e d S c i 2 0 1 2 ; 2 ( 2 ) : 6 2 - 6 5

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P r i n t I S S N : 2 2 3 1 1 6 9 6 O n l i n e I S S N : 2 2 3 1 1 7 0 X

Journal of

Medica l &Allied Sciences

Original article

Maternal short stature: A risk factor for low birth

weight in neonates

Wajihuddin Syed1 and Vipin Chandra Kamathi2

Department of Preventive Medicine, Osmania Medical College, Koti, Hyderabad 500 095,Andhra Pradesh, India.

2Department of Obstetrics and Gynecology, Mediciti Institute of Medical Sciences, Hyderabad 501 401,

Andhra Pradesh, India.

Article history: Abstract

Received 01 July 2012Revised 26 July 2012Accepted 30 July 2012

Early online 25 August 2012Print 31 August 2012

Low birth weight (LBW) is the most common cause of perinatalmortality, causing almost 30 percent of neonatal deaths. On theother hand, maternal short stature is known to cause a lot of ob-stetric complications like cephalo-pelvic disproportion and arrest oflabor, intrauterine asphyxia, intrauterine growth retardation. Theobjective of our study was to find out whether there was any signif-icant statistical association between maternal height and the birthweight of the neonate. We identified a group of low birth weightneonates (n=54) and a control group (n=51) of normal weightneonates at term in Mediciti Hospital over a period of 1 year andretrospectively looked the maternal heights for both groups. Inclu-sion criteria being mothers who delivered at term, mothers whohad a hemoglobin level more than 10 gm/dl, mothers with relative-

ly uneventful antenatal without any significant obstetric or medicalcomplications during the pregnancy, and neonates with relativelyuneventful post-natal periods without any significant pediatric ormedical complications. The odds of having been born of a motherof short stature are more than three times greater for a low birthweight baby than a normal weight baby. The mean of birth weightsof babies born to mothers of normal height is more than the meanof birth weights of babies born to mothers of short stature by277.01 gm. This study reaffirms the observation that maternalheight has a direct effect on the weight of the newborn and wepropose that maternal short stature be identified as an indepen-dent risk factor for low birth weight.

Corresponding authorWajihuddin Syed

855, Old Lancaster Road,Apt 4-A,Bryn Mawr,

PA 19010, U.S.A.Phone: +1 610 7577601

Email: [email protected]

Key words: low birth weight, maternal short stature

2012 Deccan College of Medical Sciences. All rights reserved.

ow birth weight (LBW) has been recognizedworldwide as one of the commonest causesof neonatal mortality

1. It is usually a result of

preterm birth i.e., less than 37 weeks of gestationor due to intra-uterine growth retardation in full

term births. It has been closely associated withperinatal mortality (30% of neonatal deaths)

2, in-

creased morbidity, and later consequences in theform of inhibited growth and cognitive developmentand chronic diseases. Infants who weigh 2,000-

L

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Syed W and Kamathi VC Relation between maternal stature and birth weight of neonates

J Med Allied Sci 2012;2(2)

2,499 gm at birth have a four-fold higher risk ofneonatal death than those who weight 2,500-3,499gm

3.

Various risk factors such as congenital anoma-lies or chromosomal abnormalities, diseases ofthe placenta, infections during pregnancy that af-

fect the fetus (such as rubella, cytomegalovirus,toxoplasmosis and syphilis) have been recognizedas predictors of LBW in infants. Although there issome data that maternal short stature is associatedwith LBW in Caucasians

4,5,6, there is limited infor-

mation on such association among South Asianpopulation. Maternal short stature in itself is recog-nized to increase the risk of obstetric complicationssuch as cephalopelvic disproportion, arrest of la-bor, higher rates of cesarean sections, intrauterineasphyxia, intrauterine growth retardation and low

APGAR scores. In this study we report the findingsof a retrospective analysis of maternal heights and

birth weights of babies to determine if a statisticalassociation exists between them.

Materials and Methods

A case-control study was carried out on a sampleof 105 neonates belonging to both genders basedupon the data made available to us by the depart-ment of Obstetrics and Gynecology of MedicitiHospital, Hyderabad.

Definition for LBW in our study: birth weight below2500 gm

7.

Definition for short stature: Height of the mother145 cm and below

8.

We categorized the babies in two groups depend-ing on their birth weight:

Group 1: Babies born with low birth weight (< 2500gm).

Group 2: Babies born with normal birth weight( 2500 gm).

We identified a group of low birth weight neonates(n=54) and a control group of normal weight neo-nates at term (n=51) for a period of 1 year and re-trospectively looked the maternal heights for bothgroups from the hospital records.

Inclusion criteria:

a) Mothers who delivered at term (in order to pre-vent conflict with pre-term low birth weight ba-bies).

b) Mothers with hemoglobin level more than 10gm/dl throughout the ante-natal period (in or-der to prevent conflict with low birth weightsdue to maternal anemia).

c) Mothers with relatively uneventful ante-natalperiod without any significant obstetric or med-ical complications during the pregnancy, toprevent conflict with low birth weights due toother causes.

d) Neonates with relatively uneventful post-natalperiods without any significant pediatric ormedical complications: to prevent conflict withlow birth weights due to other causes.

Results

Out of the 54 low birth weight babies, 13 were bornto mothers of short stature and 41 were born tomothers of normal stature. Out of the 51 normalweight babies, 4 were born to mothers of short sta-ture and 47 of them were born to mothers of nor-mal stature.

Table 1:Fischers exact test

Maternal

height Group 1 Group 2 Total

145 cm 13 4 17

> 145 cm 41 47 88

Total 54 51 105

The odds ratio in these groups was found to be3.72. In other words, the odds of having been bornof a mother of short stature are more than threetimes for a low birth weight baby than for a normalweight baby. The computed p value for this studywhen calculated via Fischers exact test was found

to be 0.0332 (statistically significant).

We also categorized the babies in two groups de-pending on mothers height. One, babies born tomothers of normal stature and other, babies bornto mothers of short stature. We calculated the pvalue and confidence intervals of this data by theunpaired students t-test assuming unequal va-riances (Welch correction).

Table 2: Differences between the birth weights (ingm) of neonates born to normal statute and shortstature mothers.

Birth weight innormal stature Birth weight inshort stature

Mean 2651.18 2374.18

SD 416.57 338.35

SEM 44.41 82.06

N 88 17

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Intermediate values used in calculations: t=2.9687and df=26. Standard error of difference=93.307.The computed two-tailed p value assuming un-equal variances equals 0.0063 which is statisticallysignificant. The difference between mean of birthweights of babies born to mothers of normal heightand the mean of birth weights of babies born tomothers of short stature equals 277.01 gm. 95%confidence interval of this difference range from85.21 to 468.80 gm.

Discussion

Maternal short stature as a risk factor for low birthweight has been implicated in some studies, butnot directly studied as an independent risk factor.Since the prevalence of low birth weight in devel-oping countries is blamed on malnutrition of motherand related anemia, we matched our groups forhemoglobin levels in our study to minimize con-founding. As shown by our study, there is a posi-

tive correlation between maternal stature and thebirth weight of the baby. In many studies con-ducted previously, significant birth weight differ-ences were found among mothers of variableheights. A study done by Zhang et al. of McGillUniversity, Montreal, Canada, found that mothersof short statures had significantly higher preva-lence of low birth weight, perinatal mortality, still-birth and early neonatal mortality

4. In another study

done at Johns Hopkins School of Medicine, by Wit-ter and Luke, it was found that the infants of theshorter women were symmetrically smaller thanthe infants of the taller women

5. Ferraz et al. found

an association of low height (


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of Community Medicine, Mediciti Institute of Medi-cal Sciences, Hyderabad; Dr. Mohammed IlyasKhan, Cardiology fellow, Lankenau Medical Cen-ter, Wynnewood, Pennsylvania; Dr. Barra RamReddy, Professor, Department of Physiology, Os-mania Medical College, Hyderabad; and Mo-hammed Abdur Rawoof, Intern, Department of Ob-stetrics and Gynecology, Mediciti Institute of Medi-cal Sciences, Hyderabad.

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maternal short stature a risk factor for low birth weight in neonates

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