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

Abstract

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.

Perinatal morbidity and mortality in late-term and post-term pregnancy. NEOSANO perinatal network's experience in Mexico

“…These risks persisted when controlled for potential cofounders. Caughey et al 11 reported that the incidence of emergency cesarean section also increased beyond 39 weeks of gestation, odds ratio 1.8, 2 and 2.1 for 40, 41 and 42 to 44 weeks, respectively, as compared with 39 weeks pregnancies. These findings warrant attention and indicate that these pregnancies need to be closely monitored.…”

“…Thus, the odds of chorioamnionitis were 1.4, 2 and 2.8 higher for pregnancies 40, 41 and 42 to 44 weeks, respectively, as compared with 39 weeks' pregnancies. Caughey et al, 11 in a study that included more than 100, 000 pregnant women, reported that the rate of chorioamnionitis also increased beyond 39 weeks' gestation (odds ratio when comparing to 39 weeks gestation, 1.3 and 1.7, for 40 and 42 to 44 weeks' gestation, respectively).…”

A clinical study of postdated pregnancy

“…(p<0.001), and rates of postpartum hemorrhage, endometritis and primary caesarean delivery increased at 41 weeks of gestation. 27 It has been traditionally accepted that complications are at their minimum in term pregnancies i.e. from 37-40 weeks.…”

A study of maternal and perinatal outcome in induction of labour at 40 weeks and 41 weeks of gestation

“…Neonatal risks are asphyxia, aspiration, admission to intensive care after birth, bone fracture, peripheral nerve paralysis and others. 2,[3][4][5] It has been shown that maternal complications of pregnancy could increase after 40 weeks' gestation in low-risk women, especially nullipara. 6 In low-risk pregnancy at term, it has been suggested that active management of risk through the use of preventive labour induction prior to possible development of uteroplacental insufficiency or cephalo-pelvic disproportion can improve birth outcomes and reduce caesarean section rates.…”

“…2,[3][4][5] It has been shown that maternal complications of pregnancy could increase after 40 weeks' gestation in low-risk women, especially nullipara. 6 In low-risk pregnancy at term, it has been suggested that active management of risk through the use of preventive labour induction prior to possible development of uteroplacental insufficiency or cephalo-pelvic disproportion can improve birth outcomes and reduce caesarean section rates. 7,8 Since women in Asia and Africa have been shown to have a shorter duration of pregnancy compared with European women the authors of this appraisal recommend that clinicians in those regions should regard recommendation No.…”