Fetal breathing movements in uncomplicated pregnancies. I. Relationship to gestational age

Fetal breathing movements occur in uncomplicated gestations. The relationship of fetal breathing movements recorded in 30 min sessions to gestational age and blood glucose levels is described. A total of 142 recording sessions were obtained from 45 gravid women with uncomplicated pregnancies from 24 to 41 weeks' gestation. There was a significant increase in the proportion of time spent in fetal breathing as gestational age increased. Glucose levels in a normal range (70 to 120 mg/100 ml) at the time of the recording sessions showed no correlation with the proportion of fetal breathing time.