The outcome of 140 pregnancies complicated by unexplained abdominal pain was compared with that in a comparison group of 280 women who gave birth at the same time. The two groups were comparable for maternal age and parity but the study group contained a significantly higher proportion of smokers, unmarried women, and women whose partners were unemployed (P less than 0.001). All the pregnancies resulted in livebirths. There were no statistically significant differences in birthweight, gestational age at delivery or mode of delivery between the two groups.