Comparison of maternal and fetal outcomes between delayed and immediate pushing in the second stage of vaginal delivery: systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: The second stage of labor begins with complete dilatation of the cervix until delivery of the fetus. After the cervix has fully dilated, the caregiver/nurse will provide guidance to the mother regarding the push technique for delivering the fetus (immediate pushing, IP). Because some women receive analgesic medications during labor, they might not be able to push correctly. Therefore, some obstetricians choose to postpone guiding the patient to push until the cervix is fully dilated and the fetal head has begun to descend. At this point, there is an involuntary exertion sensation (delayed pushing, DP) that saves energy and, at the same time, decreases tiredness and fatigue. The best timing for pushing during the second stage of labor is still controversial. The aim of this study was to investigate the different maternal and neonatal outcomes with IP and DP in the second stage of labor. METHODS: The Cochrane Library, EMBASE, PubMed, and Airiti Library (a Chinese database) were searched up to July 2019. Search keywords included: "labor stage, second", "delayed pushing", and "immediate pushing". Gray literature and bibliographies of articles were checked. No language restrictions were applied. Only randomized controlled trials were included. Two independent reviewers identified relevant studies and extracted data. The quality of the studies was assessed using the Cochrane's Risk of Bias tool. A random-effects meta-analysis was used to pool results. Mean differences and risk ratios were calculated with 95% confidence intervals (CIs) using Review Manager 5.3 (The Nordic Cochrane Centre, Copenhagen, Denmark, 2014). The risk of heterogeneity was reported as I2, and publication bias was visually assessed by funnel plots. RESULTS: In total, 15 studies (n = 6121 participants) were identified. Pooled results demonstrated the following. (1) As to maternal outcomes, in comparison, IP shortened the length of the second stage of labor by 40.9 (95% CI 23.6-58.2) min; however, DP decreased the total length of pushing by 25.4 (95% CI 13.9-37.0) min. The incidence of instrument-assisted vaginal delivery was significantly lower in the DP group in western countries (RR 0.85, 95% CI 0.74-0.97). In addition, the maternal postpartum fatigue score was 0.67 points lower in the DP group (95% CI - 1.09 to - 0.26). There was no statistical significance of the cesarean section rate or blood loss. (2) As to neonatal outcomes (Apgar score at 1 min), the DP group showed a higher score (by 0.19; 95% CI 0.10-0.27 points) than the IP group. CONCLUSIONS: Delayed pushing can decrease the total pushing time and decrease the fatigue score after delivery without significant adverse events compared to the early pushing group. Therefore, we recommend that caregivers instruct the pushing time at the optimal moment, which allows women to have more resting time and save energy during labor.