Maternal complications of pregnancy increase beyond 40 weeks of gestation in low-risk women.

OBJECTIVE: We sought to determine when rates of maternal pregnancy complications increase for low-risk nulliparous and multiparous women at term. METHODS: We designed a retrospective cohort study of low-risk women delivered beyond 37 weeks gestational age from 1976 to 2001. Rates of mode of delivery and maternal complications of labor and delivery were examined by gestational age with both bivariate and multivariate analyses. Statistical significance was designated by P<0.05. RESULTS: We found that among the 32,828 low-risk women who delivered at 37 completed weeks and beyond, the rates of primary cesarean delivery, operative vaginal delivery, third- or fourth-degree perineal lacerations, and chorioamnionitis all increased at 40 weeks of gestation (P<0.001), and the rate of postpartum hemorrhage increased at 41 weeks of gestation (P<0.001). These increases of rates of complications were larger and increased at an earlier gestational age among nulliparous women. CONCLUSION: We found that the risk of maternal complications for otherwise low risk nulliparous and multiparous women increased as pregnancy progressed beyond 40 weeks of gestation. Counseling of women who progress past their EDC should include comparing the risks of induction of labor to that of expectant management.

Is there a benefit to episiotomy at operative vaginal delivery? Observations over ten years in a stable population.

OBJECTIVE: Our purpose was to examine the association between maternal vaginal and perineal morbidity and episiotomy performed at operative vaginal delivery. STUDY DESIGN: We obtained data from 2041 consecutive operative vaginal deliveries and compared yearly rates of episiotomy, lacerations, and potential confounders with linear regression and stratified analyses. RESULTS: Between 1984 and 1994 the use of episiotomy for operative vaginal deliveries fell significantly (93.4% to 35.7%, R2 = 0.85, p = 0.0001). This change was associated with a rise in the rate of vaginal lacerations (16.1% to 40.0%, R2 = 0.80, p = 0.0002), a decrease in the rate of fourth-degree lacerations (12.2% to 5.4%, R2 = 0.62, p = 0.004), but no significant change in the rate of third-degree lacerations. These associations held in separate analyses stratified by parity and type of instrument used for delivery. The prevalence of other previously reported risks for perineal morbidity did not change during the study period. CONCLUSION: At our institution a statistically and clinically significant reduction in the use of episiotomy for operative vaginal deliveries was not associated with a change in the rate of third-degree lacerations but was associated with an increase in the rate of vaginal lacerations and a decrease in the rate of fourth-degree lacerations.

Is there a benefit to episiotomy at spontaneous vaginal delivery? A natural experiment.

OBJECTIVE: Our purpose was to examine the association between maternal vaginal and perineal morbidity and episiotomy performed at spontaneous vaginal delivery. STUDY DESIGN: We obtained data from 17,483 consecutive spontaneous vaginal deliveries and compared the yearly rates of episiotomy, lacerations, and potential confounders with linear regression and stratified analyses. RESULTS: Between 1976 and 1994 the use of episiotomy fell significantly (86.8% to 10.4%, R2 = 0.92, p = 0.0001). This change was associated with a fall in the rate of third- and fourth-degree lacerations (9.0% to 4.2%, R2 = 0.59, p = 0.0001) and a rise in the rate of intact perinea (10.3% to 26.5%, R2 = 0.68, p = 0.0001) and vaginal lacerations (5.4% to 19.3%, R2 = 0.77, p = 0.0001). These associations held in separate analyses stratified by parity and birth weight, except for the subgroup of nulliparous women with macrosomic infants. CONCLUSION: At our institution a large reduction in the use of episiotomy in spontaneous vaginal deliveries was associated with a significant reduction in perineal trauma in all groups of women except for nulliparous women with macrosomic infants.

Serial pattern learning in senescent rats: a comparison of acquisition performance with young and hippocampal-lesioned rats.

The acquisition of a serial pattern was assessed in young (3-month), senescent (24-month), and hippocampal-lesioned rats. All animals were trained for 25 days on a four-element, nonmonotonic pattern consisting of 14, 0, 3, and 7 food pellets, respectively. Young rats were capable of distinguishing among the elements of the series, with the exception of the 3- and 7-pellet elements, as indexed by running times. Conversely, the senescent rats were largely incapable of patterned responding, and the tracking performance of the hippocampal-lesioned rats was intermediate between those of the young and old rats. Results are discussed in terms of the possible changes that accompany aging in rodents, including age-related changes in the hippocampal system.