Is ethnicity a risk factor for developing preeclampsia? An analysis of the prevalence of preeclampsia in China

Preeclampsia is a major complication of pregnancy. Risk factors for preeclampsia include population and regional ethnicity. Chinese women living outside the Chinese mainland have a lower prevalence of preeclampsia than resident Caucasians. We performed a retrospective study to identify potential factors that may be associated with developing preeclampsia in China. A total of 67 746 pregnant women were included in this study from 2002 to 2011. Data included maternal age, maternal body mass index (BMI), age at marriage, parity, gestation and blood pressure at diagnosis, proteinuria, and birth weight. In the study period, 1301 (1.92%) nulliparous women developed preeclampsia. The prevalence of mild or severe preeclampsia was 1.42% or 0.49%, respectively. The average BMI was 21.61 kg m(-2). On the basis of the WHO BMI classification, 78.8% of women were of normal BMI, 18.3% were overweight and 2.9% were obese. A total of 37.8% of preeclamptic women had lived with the same partner for less than 1 year, which was significantly higher than those healthy pregnant women who did not develop preeclampsia (24.2%). The prevalence of preeclampsia in China is low compared with Causcasians, and the contribution to this lower prevalence may be dependent on BMI or lifestyle including period of cohabitation with the partner. Our data suggest that Chinese ethnicity may be a factor responsible for the low risk of developing preeclampsia in the populations studied.