METHOD AND MATERIAL: Fresh, vaginally delivered placentae from ten normotensive pregnant women and nine women with pre-eclampsia were carefully dissected and 4 gm each of amnion, chorion laeve, placental plate chorion, fetal placenta (fetal surface of the placenta) and maternal placenta (surface of the placenta attached to the uterine wall) were obtained. These tissues were then thoroughly washed in a 0.5 M phosphate buffer, pH 7.5, at room temperature and then individually homogenized for one minute in 4 ml of the same buffer. After centrifugation the supernatant was removed. The pellet was re-suspended in buffer, re-homogenized and then centrifuged. The supernatant was removed and the procedure was repeated once again and the three supernatants of each tissue were pooled. Endothelin-1 was estimated by RIA. All results are presented as mean+/-SEM. Statistical analysis was performed using students 't' test for unpaired samples and a 'p' value of <0.05 was considered significant.
RESULTS: In tissues from normotensive pregnant women, no significant differences were evident in endothelin-1 concentrations in the chorion laeve, fetal placenta and maternal placenta but were significantly higher than those in the amnion and placental plate chorion (p<0.01). In tissues from pre-eclamptic women, no significant differences were evident between endothelin-1 concentrations in the chorion laeve, placental plate chorion and fetal placenta. Mean endothelin-1 concentration in the amnion and maternal placenta were significantly lower than those in chorion laeve, placental plate chorion and fetal placenta (p<0.01). Endothelin-1 concentrations were significantly higher in the amnion, chorion laeve, placental plate chorion and fetal placenta from women with pre-eclampsia when compared to tissues from normotensive pregnant women (p<0.01).
CONCLUSIONS: Endothelin-1 levels were significantly higher in the placental tissues from women with pre-eclampsia. Endothelin-1, being a powerful vasoconstrictor, could cause significant vasoconstriction in the placental vasculature, and alterations in endothelin-1 levels in placental vasculature may therefore have a role in the pathogenesis of pre-eclampsia.
METHODS: Women at term with one transverse lower segment cesarean delivery who were suitable for and who planned VBAC were approached to participate. Participants were randomly assigned to weekly membrane sweeping or weekly vaginal assessment for Bishop score until delivery. Participants and delivery providers were blinded to the allocated treatment. Standard obstetric care was given to all participants. The primary outcome was onset of labor which was defined as the presence of spontaneous regular and painful contractions that cause cervical dilation to at least 3 cm or prelabor rupture of membranes. Secondary outcomes included induction of labor and repeat cesarean delivery.
RESULTS: One hundred eight women were randomly assigned to membrane sweeping and 105 to control. The spontaneous labor rate was 78.5% compared with 72.1% (relative risk [RR] 1.1, 95% confidence interval [CI] 0.9-1.3; P=.34), the induction of labor rate was 12.1% compared with 9.6% (RR 1.3, 95% CI 0.6-2.8; P=.66), and the all-cause cesarean delivery rate was 40.2% compared with 44.2% (RR 0.9, 95% CI 0.7-1.2; P=.58) for the membrane sweeping and control groups, respectively. Gestational age at delivery (mean+/-standard deviation) of 39.6+/-1.0 weeks for the membrane sweeping group compared with 39.6+/-0.9 weeks for the control group (P=.84) was no different.
CONCLUSION: Serial membrane sweeping at term in women who planned VBAC has no significant effect on the onset of labor, pregnancy duration, induction of labor, or repeat cesarean delivery.
CLINICAL TRIAL REGISTRATION: ISRCTN, isrctn.org, ISRCTN55163179.
LEVEL OF EVIDENCE: I.
METHODS: Parous women with favorable cervixes after amniotomy for labor induction were randomized to immediate titrated oxytocin or placebo intravenous infusion in a double-blind noninferiority trial. After 4 hours, study infusions were stopped, the women were assessed, and open-label oxytocin was started if required. Maternal satisfaction with the birth process was assessed with a 10-point visual numerical rating scale (lower score, greater satisfaction).
RESULTS: Vaginal delivery rates at 12 hours were 91 of 96 (94.8%) compared with 91 of 94 (96.8%) (relative risk 0.98, 95% confidence interval [CI] 0.92-1.04, P=.72), and maternal satisfaction on a visual numerical rating scale (median [interquartile range]) was 3 [3-4] compared with 3 [3-5], P=.36 for immediate compared with delayed arm, respectively). Cesarean delivery, maternal fever, postpartum hemorrhage, uterine hyperactivity, and adverse neonatal outcome rates were similar between arms. The immediate oxytocin arm had a shorter amniotomy-to-delivery interval of 5.3±3.1 compared with 6.9±2.9 hours (P