45 Physical activity in pregnancy: Predictive of labor outcomes?

Abstract

Physical activity in pregnancy is associated with decreased risks of adverse pregnancy outcomes such as gestational diabetes and preeclampsia. However, the relationship between physical activity during pregnancy and subsequent labor outcomes is unknown. Since labor is a physically arduous process, we tested the hypothesis that increased physical activity in pregnancy is protective against adverse labor outcomes. This is a secondary analysis of a prospective cohort study in which pregnant patients were administered the Kaiser Physical Activity Survey (KPAS) in each trimester. The primary outcome for this analysis was duration of the 2nd stage of labor. Secondary outcomes were duration of active stage, prolonged 1st and 2nd stage, mode of delivery, rates of 2nd stage cesarean section, operative vaginal delivery, severe perineal lacerations and postpartum hemorrhage. These outcomes were compared between patients with and without high physical activity levels, defined as overall KPAS score ≥75th percentile in the 3rd trimester. Multivariable logistic regression was used to adjust for obesity. There were 811 patients with a complete KPAS included in this analysis. The median KPAS score was 9.5 (8.2, 10.8). 203 patients (25%) had high physical activity levels in pregnancy. There was no difference in the duration of 2nd stage of labor between patients with and without high physical activity levels (0.97 ± 2.08 vs 1.29 ± 2.94 hours, p=0.15). The duration of active labor was significantly shorter in patients with increased physical activity (7.43 ± 6.29 vs 5.77 ± 4.97 hours, p=0.01). Patients with high physical activity levels were significantly less likely to have a prolonged 1st stage (9.8% vs 19.4%, p<0.01, RR 0.51 [95% CI 0.32, 0.79]). Rates of prolonged 2nd stage, cesarean section, operative vaginal deliveries and perineal lacerations were similar between groups. Patients that are physically active in pregnancy may have a shorter duration of active labor. Further research should investigate the impact of initiatives to increase physical activity in pregnancy on labor.