LAUSR

BACKGROUND The ARRIVE trial demonstrated the benefit of elective induction of labor at 39 weeks gestation. Obstetrics departments across the United States faced the conundrum of how best to adapt clinical practice in light of these data while managing logistical constraints. OBJECTIVE To determine if there were changes in obstetric practices and perinatal outcomes in the United States after the ARRIVE trial publication. METHODS This was a population based, retrospective cohort study of low-risk nulliparous women who initiated prenatal care by 12 weeks gestation with singleton, non-anomalous pregnancies that delivered at ≥ 39 weeks. Data were obtained from the US Natality database. The pre-ARRIVE group were women who delivered between January 1, 2015 and December 31, 2017. The post-ARRIVE group consisted of women who delivered between January 1 and December 31, 2019. Births that occurred in 2018 were excluded. Practice outcomes were rate of induction of labor, timing of delivery, and cesarean delivery rate. Adverse maternal outcomes were blood transfusion and admission to medical intensive care units (MICU). Adverse neonatal outcomes were need for assisted-ventilation (immediate and >6 hours), 5-minute APGAR score <3, neonatal intensive care unit (NICU) admission, seizures, and surfactant use. Univariate and multivariate analyses were performed. Trends were tested across the time period represented by the pre-ARRIVE group using Cochran-Armitage trend test. RESULTS There were 1,966,870 births in the pre-ARRIVE group and 609,322 in the post-ARRIVE group. The groups differed in age, race, body mass index, marital status, infertility treatment, and smoking history (p<0.001). After adjusting for these differences, the post-ARRIVE group was more likely to undergo induction (36.1% versus 30.2%; aOR=1.36 (1.36-1.37)) and deliver by 39+6 weeks of pregnancy (42.8% versus 39.9%; aOR=1.14 (1.14-1.15)). The post-ARRIVE group had a significantly lower rate of cesarean delivery than the pre-ARRIVE group (27.3 % versus 27.9%; aOR=0.94 (0.93-0.94)). Patients in the post-ARRIVE group were more likely to receive a blood transfusion (0.4% versus 0.3%; aOR=1.43 (1.36-1.50)), and be admitted to MICU (.09% versus .08%; aOR=1.20 (1.09-1.33)). Neonates in the post-ARRIVE group were more likely to need assisted ventilation at birth (3.5% versus 2.8%; aOR=1.28 (1.26-1.30)) and > 6 hours (0.6% versus 0.5%; aOR=1.36 (1.31-1.41)). The neonates in the post-ARRIVE group were more likely to have low 5-minute APGAR (0.4% versus 0.3%; aOR=0.91 (0.86-0.95)). NICU admission did not differ between the two groups (4.9% versus 4.9%; aOR=1.01 (0.99-1.03)). There were no differences in neonatal seizures (0.04% versus 0.04%; aOR=0.97 (0.84-1.13)), and surfactant use (0.08% versus 0.07%; aOR=1.05 (0.94-1.17)) between the two groups. CONCLUSION There were more inductions of labor, more deliveries at 39 weeks gestation, and fewer cesarean deliveries in the year after the ARRIVE trial publication. The small but statistically significant increase in some adverse maternal and neonatal outcomes should be explored to determine if there was a relationship with concurrent changes in obstetric practices.