['To examine plasma levels of motilin and somatostatin throughout pregnancy.', 'Prospective observational study.', 'University Hospital, Norway.', 'Eight healthy pregnant women (aged 24-38 years) six of them primigravidae and eight healthy non-pregnant women of similar age with ovulatory menstrual cycles.', 'In the pregnant women blood samples were obtained at 4-week intervals from 8 weeks gestation throughout pregnancy and again at 5 days and 28 days postpartum. In the non-pregnant controls blood samples were obtained on cycle days 4, 7, 10, 13, 14, 15, 18, 21 and 24.', 'Plasma levels of motilin and somatostatin.', 'Plasma concentrations of both motilin and somatostatin rose continuously during pregnancy, and motilin levels increased still further to a peak of 165.1 (SE 35.8) pmol/l at 5 days postpartum. Plasma motilin levels were significantly higher during the third trimester and at 5 days postpartum compared with non-pregnant controls (P less than 0.0001). The highest plasma somatostatin levels were found at 40 weeks gestation and at 5 days postpartum (mean 32.1 SE 1.1 pmol/l). Somatostatin levels were significantly higher during the second and third trimester and the postpartum period compared with levels in the follicular phase of the non-pregnant controls (P less than 0.0001).'] Are plasma concentrations of motilin and somatostatin increased in late pregnancy and postpartum?