Birthweight for gestation standards were derived in a study of 5,872 women with ascertainable menstrual dates in Harare, Zimbabwe. The smoothed 5th, 50th and 95th centiles of birthweight for gestation were described for 24 to 42 weeks and these fitted linear quadratic functions. Male infants were significantly heavier than females from 36 weeks onwards and parity differences appeared at 38 weeks gestation. The results suggest that in this population, low birthweight should be defined as 2,000gm or less, rather than a birthweight of less than 2,500gm.
PIP: A standard birthweight curve was generated for Zimbabwe from birth weights of 5872 liveborn normal singleton infants from spontaneous labor born between August 1986-May 1987 at the Municipal clinics and maternity hospitals in Harare, Zimbabwe. Gestational ages, from 24-42 weeks, were ascertained from known menstrual dates or ultrasound dating. The curves were smoothed by polynomial regression at 5th, 10th, 50th, 90th and 95th percentiles. The best fit of the smoothed to the actual values occurred near term. Mean birthweights of males and females were significantly different. Male and female infants of multiparous women averaged 4.4% and 3.8% heavier than those of nulliparous women from 38 weeks onward. These infants were midway in weight between other African and European birth weight. It was recommended that low birth weight infants in Zimbabwe be defined as 2000 g rather than 2500 g.