Fetal movements were measured by 37 pregnant women during a 10 min period while they were lying on their left side at various times during the day. The fetal activity rate increased during the day with the highest rates in the evening. Preliminary assessments of fetal movement and serum hPL [human placental lactogen] levels in pregnant women suggest that the 2 tests might complement each other in providing more information about the status of the placenta and fetus.