Distribution of birthweights of hospital born Pakistani infants

To determine the distribution of birthweights among newborns and its relationship to specific sociodemographic and medical factors.

All babies born after 24 weeks of gestation between November, 1994, and June, 1996 were included irrespective of the fact whether they were live or still borns. Infants having birth weights 2.5 to 4 kg were termed as normally weighed babies, under 2.5 kg as low birth weight and above 4 kg as macrosomics. Data gathered included sociodemographic and medical variables. Birthweights of the newborns were measured without clothes to the nearest 10 gm on an infants beam balance within 15-30 minutes of birth. The baby scale was calibrated daily for accuracy.

Mean birth weight of the newborns was 2.91 kg. Weight of 78% babies ranged from 2.5 to 4 kg, 19% had low birth weight and 3% of neonates weighed above 4 kg. Of 1156 low birth weight babies 70% were preterm, 16% were growth retarded and 14% were both premature and growth retarded. Macrosomic babies were commonly born to the mothers who were either 35 years age or more or were para > 5, whereas 59% cases of low birth weight was associated with primipartiy and grandmultiparity. Causes of low birth weight included APH, twin pregnancy, PROM and severe preeclampsia and eclampsia. Risk factors for fetal macrosomia were advanced maternal age and parity, postdatism and diabetes mellitus.

In this study the relative impact of some of the factors related to birthweight in reference to our population was highlighted. Further explorations preferably in population based studies are required as birthweight data is essential for monitoring and evaluating the progress towards achieving national goals for lowering neonatal and infant morbidities and mortalities.