Fetal respiratory movements observed by ultrasound during abnormal pregnancies

Observations of fetal respiratory movements were carried out during 35 pregnancies with complications likely to indicate increased fetal risk. Fetal breathing was demonstrated in 25 of 35 patients studied, and in 29 of 47 separate examinations. Of 17 patients delivering after 36 weeks gestation in whom observations were made with two weeks of delivery, three did not demonstrate fetal breathing. Infants born from these pregnancies were severely growth retarded in two instances and light for dates in the other. Although absent fetal breathing is likely to detect increased fetal hazard near term, the time and expense needed for accurate recording of fetal breathing will restrict application of the technique in the meantime.