[Fetal heart rate monitoring during maternal swimming].

Fetal physiology during swimming in pregnancy has remained unclear. To assess the fetal status, the fetal heart rate (FHR) was measured during maternal swimming. We studied individually a group of seventeen women in normal pregnancy (during their third trimester, 35-38th week) who participated in a maternal swimming class. We adapted the Doppler ultra-sound transducer for underwater use and attached it to the mothers' abdomen. FHR was recorded before, during and after swimming. The group swam from 375 to 750 meters in 33 to 41 minutes. During swimming, motion artifacts interfered with the FHR signal and we were only able to detect FHR in eleven in the group. The mean FHR rose significantly during swimming in eight of eleven women compared to the FHR recorded before the exercise. The FHR pattern was reactive and baseline variability was preserved in all cases. No pathological deceleration was seen. It is concluded that maternal swimming under such class conditions is safe for the fetus.