Abstract

The aim of this retrospective study was to explore the effects of pre-pregnancy body mass index and gestational weight gain on neonatal birth weight in Taiwan.Study subjects included two hundred and sixty three women who delivered their babies at two local hospitals in southern Taiwan. Initial data included maternity records on age, parity, socio-economic status, body mass index (BMI), pregnancy weight gain, neonatal gender, and neonatal birth weight. The mean age of 263 women was 29.99 years (range 19 - 42). The mean BMI was 21.19 kg/m² (range 16.22 - 32.05), and the mean pregnancy weight gain was 13.98 kg (range 3 - 33.5). The mean neonatal birth weight was 3192.57 gm (range 2120 - 4390).  Mothers whose BMI was 24 - 27 had significantly higher neonatal birth weight than those mothers with a BMI > 27 and < 18.5) (F = 5.816, p = 0.001). After dividing the weight gain during pregnancy into four groups based on the recommendation of the Department of Health in Taiwan, our results show differences between maternal weight gain and neonatal body weight (F = 9.49, p < 0.001). Pregnant women with a weight gain less than 10 kg resulted in deliveries of neonates with lower birth weight (113.94, 237.62 and 332.58 gm) than those mothers who gained 10 - 14, 14 – 16 kg, and more than 16kg. Multiple regression models control for other maternal and neonatal characteristics were able to document, weight gain as being more strongly associated with neonatal birth weight than pre-pregnancy body mass index. Neonatal birth weight was not correlated with maternal working status, socio-economical status and was not differentiated between primipara and multipara status. Conclusively, pre-pregnancy BMI and prenatal weight gain are related to neonatal birth weight. These results suggest that the pre-pregnancy BMI and prenatal weight gain should be among the most important concerns for providers offering prenatal services. Hopefully these findings will serve as a useful reference for prenatal nurses and will reinforce health insurance departments’ efforts to ensure quality prenatal care.

 Key words: Body mass index, pregnancy weight gain, neonatal birth weight