title: Placental vascular resistance using umbilical velocimetry in patients undergoing cesarean section for fetal distress.
abstract: Peak systolic (S) to lowest end-diastolic (D) ratios (S/D) of umbilical velocimetry have been used to assess downstream placental vascular resistance and predict adverse pregnancy outcome. The purpose of this study is to assess S/D ratios in patients undergoing cesarean section for clinical fetal distress. Fifty-six patients were identified who had umbilical velocimetry performed during antepartum fetal surveillance (nonstress testing and amniotic fluid index) within 7 days of undergoing cesarean section for fetal distress at Women's Hospital (Los Angeles, CA). The mean gestational age at delivery was 36.5 +/- 2.5 weeks. Thirty (53.6%) patients had elevated S/D ratios (greater than 3), 24 (42.9%) had abnormal amniotic fluid indices, and 20 (35.7%) had abnormal nonstress testing. Group 1 (N = 30) patients delivered small-for-gestational-age (SGA) fetuses and group 2 (N = 26) patients delivered appropriately grown (AGA) fetuses. In group 1, 24 (80%) patients had abnormal S/D ratios and 16 (53.3%) had abnormal amniotic fluid indices, compared to only 6 (23.1%) with abnormal S/D ratios and 8 (30.8%) with abnormal amniotic fluid indices in group 2 (p less than .05). In contrast, 14 (53.8%) of the 26 patients in group 2 had abnormal nonstress testing compared to only 6 (20%) of the 30 patients in group 1 (p less than .05). Eighteen (69.2%) of the 26 patients in group 2 were post-term pregnancies; 20 (66.7%) of the 30 patients in group 1 had chronic hypertension, pregnancy-induced hypertension, or superimposed preeclampsia.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Obstetrics and Gynecology, University of Southern California School of Medicine, Los Angeles.
authors.forename: H S
authors.initials: HS
authors.lastname: Brar
authors.forename: L D
authors.initials: LD
authors.lastname: Platt
mesh_terms: D000328:Adult; D000653:Amniotic Fluid / Q000502:physiology; D001783:Blood Flow Velocity; D002585:Cesarean Section; D005260:Female; D005316:Fetal Distress; D006801:Humans; D010920:Placenta / Q000098:blood supply*; D011247:Pregnancy; D012189:Retrospective Studies; D014463:Ultrasonography; D014469:Umbilical Arteries / Q000503:physiopathology*; D014655:Vascular Resistance