Ethnic differences in prenatal growth and the association with maternal and fetal characteristics

Objectives The objectives of this study were to determine ethnic differences in prenatal growth and to examine their association with differences in maternal and fetal characteristics such as maternal height, weight, age, parity and fetal gender. Methods A total of 1494 women from Rotterdam, The Netherlands, with a low-risk pregnancy who participated in a population-based cohort Study, the Generation R Study, were offered three ultrasound examinations during pregnancy. Multilevel modeling was applied to determine ethnic differences in (estimated) fetal weight (including birth weight) and in the separate biometric variables that were used to calculate the estimated fetal weight (abdominal circumference, head circumference and femur length). Additionally the association of ethnic differences with maternal and fetal characteristics (i.e. maternal weight, height, age, parity and fetal gender) was studied. Results Turkish, Cape Verdian, Surinamese-Creole and Surinamese-Hindustani women had on average smaller fetuses than the native Dutch women. The differences became more pronounced towards term. In the Turkish group the differences were no longer statistically significant when adjusted for maternal weight, height, age, parity and fetal gender. In the Cape Verdian, Surinamese-Creole and Surinamese-Hindustani groups the differences decreased after adjustment (31%, 16% and 39%, respectively). Conclusions This study shows that there are ethnic differences in fetal growth, which to a large extent may be attributed to differences in maternal weight, height, age and parity. For some ethnic groups, however, additional factors are involved, as differences remain significant after correction for fetal and maternal characteristics. Copyright (c) 2005 ISUOG. Published by John Wiley & Sons, Ltd.