Maternal characteristics largely explain poor pregnancy outcome after hyperemesis gravidarum

Objective: To describe the characteristics of women who suffer from hyperemesis gravidarum, and explore the independent effect of hyperemesis gravidarum on pregnancy outcome. Study design: In The Netherlands Perinatal Registry, we used all data on singleton pregnancies of at least 24 weeks and 500 g without congenital anomalies in the years 2000-2006. We examined the characteristics of women who suffered from hyperemesis gravidarum and their children. Results: Women who suffered from hyperemesis gravidarum were slightly younger; more often primiparous, of lower socio-economic status, of non-Western descent and substance abusers; had more often conceived through assisted reproduction techniques and more often had pre-existing hypertension, diabetes mellitus and psychiatric diseases than women who did not suffer from hyperemesis gravidarum. Also, their pregnancies were more often complicated by hypertension and diabetes and they more often carried a female fetus. Pregnancies complicated by hyperemesis gravidarum significantly more often had an adverse outcome (prematurity or birth weight below the 10th percentile). The increased risk of adverse pregnancy outcomes after hyperemesis gravidarum was largely explained by the differences in maternal characteristics (crude OR 1.22 (95% CI 1.10-1.36), adjusted OR was 1.07 (95% CI 0.95-1.19)). Conclusion: Hyperemesis gravidarum is associated with adverse pregnancy outcomes. This is largely explained by differences in maternal characteristics. Given the impact of the early environment on later health (which is independent of size at birth), studies that aim to assess the long-term consequences of hyperemesis gravidarum need to be given high priority. (C) 2011 Elsevier Ireland Ltd. All rights reserved