Induction of labor and the relationship to cesarean delivery: A review of 7001 consecutive inductions.

OBJECTIVE: The goal of this project was to study the increasing risk of induction of labor in a community hospital and to determine whether it had an adverse effect on the rate of cesarean delivery. STUDY DESIGN: From January 1, 1990, through July 31, 1997, 18,055 consecutive singleton pregnancies in women who were candidates for labor were reviewed via a comprehensive perinatal database. The risk of and indication for induction were reviewed. Cesarean delivery rates were calculated for nulliparous and multiparous patients by indication for induction and were compared with rates for patients who had spontaneous labor. Overall trends in cesarean delivery were reviewed for the duration of the study period. RESULTS: The annual induction rate significantly rose from 32% to 43% at the conclusion of the study period. Labor was induced in nearly 40% of nulliparous patients. Postdate pregnancy was the most common indication for induction, although few patients were at or beyond 42 weeks' gestation. The cesarean delivery rate remained at or below 20% for the years of the study. No increase was noted in spite of the increasing risk of induction. However, for nulliparous patients who had elective induction of labor, the risk of cesarean delivery was twice that of nulliparous patients who had spontaneous labor. CONCLUSION: The use of induction methods has significantly increased in this community hospital. More than 40% of patients are now candidates for induction. The cesarean delivery rate remains low in this facility in spite of a marked increase in risk of operative delivery for nulliparous patients who undergo induction.

Changing patterns in regionalization of perinatal care and the impact on neonatal mortality.

OBJECTIVE: Our goal was to study changing patterns of low-birth-weight outcome over the past decade as deregionalized perinatal care has occurred. STUDY DESIGN: Live births and neonatal mortality for two 5-year periods (1982 to 1986 vs 1990 to 1994) were calculated by hospital of delivery in the state of Missouri. Self-designated level of perinatal care was contrasted with number of deliveries and nursery census to evaluate outcome. Regression models were constructed to compare outcome between levels of care. RESULTS: There has been a significant shift of deliveries into self-designated level II and III perinatal centers. However, this is largely a result of redesignation of care rather than an actual increase in acuity or census. The relative risk of neonatal mortality for very-low-birth-weight infants is 2.28 in level II centers compared with level III centers, and is unchanged (2.57) from 10 years earlier. Nearly 14% of very-low-birth-weight deliveries still occur at non-level III centers. CONCLUSION: Changing patterns of perinatal regionalization have not improved outcome for inborn infants < 1500 gm except in level III centers. Attempts should be made to deliver very-low-birth-weight infants in level III centers.

Maternal oxygen desaturation with intravenous magnesium therapy.

OBJECTIVE: To describe the occurrence, treatment, and outcome of maternal oxygen desaturation during magnesium sulfate therapy. METHODS: A post hoc analysis of a randomized double-blind trial, designed to determine if mothers at risk for premature delivery treated with phenobarbital and vitamin K had less frequent intracranial hemorrhage in their newborns, was done. A subset of these patients at imminent risk for delivery received both intravenous magnesium sulfate and intravenous study drug (phenobarbital or placebo) and was monitored with maternal oxygen saturation monitoring. RESULTS: One hundred one women (29%) in the trial had pulse oximetry; 47 were assigned to placebo and 54 to the treatment group. The placebo and treatment groups had the following similarities: mean lowest oxygen saturation by pulse oximeter (93.4% +/- 3.0 compared with 93.1% +/- 3.3). mean highest magnesium levels (6.3 mEq/L +/- 1.5 compared with 6.2 mEq/L +/- 0.9), frequencies of desaturation events defined as oxygen saturation below 90% (11% compared with 11%), gestational age at delivery, birth weight, Apgar scores, and cord arterial pH. Using regression analysis, multiple gestation was the only one of 14 independent variables associated with low maternal oxygen saturation. Preeclampsia was not associated with a greater risk of desaturation. The statistical power of this study is limited by its small sample sizes. CONCLUSION: Maternal oxygen desaturation occurs commonly with intravenous magnesium therapy, does not occur more frequently with simultaneous administration of intravenous phenobarbital, and does not cause decompensation in maternal or fetal status. Multiple gestation may be associated with lower maternal oxygen saturation.

Perinatal factors predicting severe intracranial hemorrhage.

The objective of this paper is to determine the importance of perinatal factors predicting occurrence of severe intracranial hemorrhage (ICH) in premature newborns. A post-hoc analysis of a previously published randomized, double-blinded, prospective trial was performed. Logistic regression analysis was used to assess the importance of obstetrical variables and umbilical cord blood coagulation studies and acid-base status in predicting severe ICH (grades 3 and 4). The trial lasted 42 months; 401 pregnant women were invited to participate and 48 declined. The most important predictors of severe ICH in order of decreasing significance were: gestational age at delivery (p=0.0001), duration of painful labor (p=0.0077), duration of antenatal antibiotic therapy (p=0.0203), maternal age (p=0.0247), and factor X activity in umbilical cord blood (p=0.0302). Mode of delivery, cord blood acid-base, and coagulation status did not correlate with severe ICH. The majority of severe ICHs were late in onset; only two of 31 were known to have occurred in the first 24 hr of life. Gestational age, duration of painful labor, duration of antibiotic therapy, and maternal age were the most important predictors of severe ICH.