Inverse association between severe nausea and vomiting in pregnancy and some congenital abnormalities.

The objective of the study was to investigate the possible association between nausea and vomiting in early pregnancy and congenital abnormalities. The prevalence of medically-recorded severe nausea and vomiting in early pregnancy in cases with congenital abnormalities and their available matched population controls without any defect was compared in the population-based large data set of the Hungarian Case-Control Surveillance System of congenital abnormalities, 1980-1996. Of 22,843 cases with as 25 different congenital abnormality groups, 1,713 (7.5%) cases had mothers with medically recorded and treated severe nausea and vomiting during pregnancy. Of 38,151 matched population controls, 3,777 (9.9%) had mothers with severe nausea and vomiting (adjusted prevalence odds ratio (POR) with 95% CI: 0.74, 0.68-0.79). Five congenital abnormality groups: cleft lip with or without cleft palate (0.50, 0.37-0.70), posterior cleft palate (0.53, 0.32-0.89), renal a/dysgenesis (0.23, 0.06-0.96), obstructive defects of urinary tract (0.32, 0.18-0.58), and cardiovascular malformations (0.68, 0.57-0.81) had mothers with a lower prevalence of severe nausea and vomiting in pregnancy (adjusted PORs with 95% CI included in parentheses). Of 25 congenital abnormality groups, 22 had POR lower than 1. Thus in this study the mothers of cases with congenital abnormalities were 26% less likely to have had severe nausea and vomiting in early pregnancy than the mothers of population controls without congenital abnormalities.