Prolonged pregnancy. I. Observations concerning the causes of fetal distress
Leveno, K.J.; Quirk, J.G.; Cunningham, F.G.; Nelson, S.D.; Santos-Ramos, R.; Toofanian, A.; DePalma, R.T.
American Journal of Obstetrics and Gynecology 150(5 Pt 1): 465-473
1984
ISSN/ISBN: 0002-9378 PMID: 6388333 Document Number: 231809
During a 2 yr prospective investigation of prolonged pregnancy in 727 women, 59 (8%) were delivered by cesarean section for fetal distress. This condition was diagnosed by means of electronic fetal heart rate monitoring in 47 of the women, and the patterns were unexpectedly characteristic of umbilical cord compression rather than uteroplacental insufficiency. Blinded sonar examinations were performed in 213 women, and the incidence of cesarean section for fetal distress as now described was significantly increased in those with oligohydramnios (2 of fewer 1 cm pockets of amniotic fluid). The pathophysiology of fetal distress in prolonged pregnancy is typically oligohydramnios that leads to compromised umbilical cord perfusion, rather than uteroplacental insufficiency.