Braxton Hicks' contractions and motor behavior in the near-term human fetus.

The transient relationship between Braxton Hicks' contractions and fetal motor behavior was studied in 14 healthy nulliparous women near term. Two-hour recordings of fetal heart rate and uterine contractions and of real-time scanning for fetal body movements, breathing, and eye movements were made. The recordings were divided into state 1F and non-state 1F. Braxton Hicks' contractions were not influenced by fetal behavioral states and state changes were not related to these contractions. Fetal body movements did not stimulate contractions, but contractions coincided with a specific clustering of body movements during the ascending part of contractions. Breathing was clustered during the descending part of short-lasting contractions but decreased gradually during the long-lasting ones. Heart rate variation was increased during contractions.