Influence of Maternal Height, Weight and Body Mass Index on Birthweight in an Asian Population

Abstract

Objective: Birthweight is an important parameter to both obstetricians and neonatologists. Gestational age-specific birthweight gives useful information on the possibility of intra-uterine growth restriction or overgrowth. The aim of this study is to construct reference gestation age-specific birthweight percentile charts for Asian babies with particular reference to maternal height, weight and body mass index (BMI).Method: Birthweights of 25,141 babies born in KK Hospital, Singapore in 1994 and 1995 were analysed. Results: The median (10 90 percentiles) maternal height was 155 cm (148 cm 163 cm), corrected midtrimester maternal weight was 59.9 kg (48.4 kg 75.6 kg ) and BMI was 24.8 kg/m (20.6 kg/m 31.2 kg/m). All 3 parameters were positively associated with larger birthweights. The mean birthweights for tall and short mothers were 3219g versus 3014g (p <0.001), heavy and light mothers 3337g versus 2845g (p<0.001) and, overweight and underweight mothers 3276g versus 2909g (p<0.001) respectively. Besides race, parity and gestational differences, anthropometric differences in maternal height, weight, body mass index are important factors that affect birthweight.Conclusion: The availability of local gestation age-specific birthweight centile charts are essential for obstetricians & neonatologists in their perinatal practice. Gestational age-specific birthweight charts need to take into account maternal height, weight and BMI of the local population in order to be useful to practicing clinicians. These charts also allows comparison of changes in local birthweights over the decades and for different generations.