Aboukhater Diana, Hayasaka Misa, Furukawa Natsume, Jones Sora, Grantz Katherine L, Kawakita Tetsuya
Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, VA.
Faculty of Medicine, International University of Health and Welfare, Narita, Chiba, Japan.
Am J Obstet Gynecol. 2025 Jul 10. doi: 10.1016/j.ajog.2025.07.014.
This systematic review and meta-analysis aimed to investigate the association between the duration of the second stage of labor-including both total duration and the active pushing-and adverse maternal and neonatal outcomes, stratified by parity.
We conducted a comprehensive literature search of MEDLINE, Embase, and Cochrane databases from inception through October 2024.
Eligible studies reported maternal or neonatal outcomes related to second-stage duration or pushing duration, with data stratified by parity. Studies involving multiple gestations and those with prior cesarean deliveries were excluded.
Two independent reviewers performed data extraction and quality assessments; disagreements were resolved by a third reviewer. Cesarean delivery was prespecified as the primary maternal outcome, while other maternal and neonatal outcomes were analyzed as secondary outcomes. To quantify the association between prolonged second-stage or pushing duration (≥60 minutes) and each outcome, we performed post-hoc random-effects meta-analyses (Mantel-Haenszel) restricted to outcomes for which ≥2 eligible studies used <60 minutes as the reference category. Thus, only those studies meeting this criterion were pooled.
In total, 26 studies met the inclusion criteria: 18 retrospective cohort studies, 1 prospective cohort study, 6 secondary analyses of clinical trials, and 1 randomized controlled trial. Among nulliparous individuals, a second stage exceeding 1 hour was associated with increased risks of cesarean delivery, blood transfusion, perineal laceration, and chorioamnionitis; pushing beyond 1 hour was similarly associated with cesarean delivery and postpartum hemorrhage. Comparable trends were observed in multiparous individuals. Across both parity groups, neonatal intensive care unit admission was more frequent when the second stage exceeded 1 hour. In nulliparous individuals, pushing beyond 60 minutes was significantly associated with a low 5-minute Apgar score and neonatal intensive care unit admission. Only one study specifically evaluated pushing duration among multiparous individuals, finding no significant associations with neonatal morbidity.
Evidence indicates maternal and neonatal morbidity begins to rise within the first hour of the second stage and climbs with further prolongation, although the exact tipping point varies. Active pushing ≥60 minutes was associated with an increased risk of maternal morbidity, while neonatal effects are less certain; in nulliparas, we found an increased neonatal morbidity with pushing ≥60 minutes. Because the pooled estimates rely on a small, clinically heterogeneous subset of studies, these findings should be viewed with caution. Future studies should examine the individualized approach to determine the optimal timing of intervention, stratified by parity and epidural status, to refine duration guidelines.
本系统评价和荟萃分析旨在研究产程第二阶段的时长（包括总时长和有效用力时长）与孕产妇和新生儿不良结局之间的关联，并按产次进行分层分析。
我们对MEDLINE、Embase和Cochrane数据库进行了全面的文献检索，检索时间跨度从建库至2024年10月。
符合条件的研究报告了与第二产程时长或用力时长相关的孕产妇或新生儿结局，并按产次分层提供数据。排除涉及多胎妊娠和既往有剖宫产史的研究。
两名独立的审阅者进行数据提取和质量评估；如有分歧，由第三名审阅者解决。剖宫产被预先指定为主要的孕产妇结局，而其他孕产妇和新生儿结局作为次要结局进行分析。为了量化第二产程延长或用力时长延长（≥60分钟）与各结局之间的关联，我们进行了事后随机效应荟萃分析（Mantel-Haenszel法），仅限于≥2项符合条件的研究将<60分钟作为参照组的结局。因此，仅汇总符合该标准的研究。
共有26项研究符合纳入标准：18项回顾性队列研究、1项前瞻性队列研究、6项临床试验的二次分析以及1项随机对照试验。在初产妇中，第二产程超过1小时与剖宫产、输血、会阴裂伤和绒毛膜羊膜炎风险增加相关；用力超过1小时同样与剖宫产和产后出血相关。经产妇中也观察到类似趋势。在两个产次组中，第二产程超过1小时时，新生儿重症监护病房入院率更高。在初产妇中，用力超过60分钟与5分钟Apgar评分低和新生儿重症监护病房入院显著相关。只有一项研究专门评估了经产妇的用力时长，未发现与新生儿发病率有显著关联。
有证据表明，产程第二阶段的第一个小时内，孕产妇和新生儿发病率就开始上升，并随着产程进一步延长而攀升，尽管确切的临界点有所不同。有效用力≥60分钟与孕产妇发病风险增加相关，而对新生儿的影响尚不确定；在初产妇中，我们发现用力≥60分钟会增加新生儿发病率。由于汇总估计值依赖于一小部分临床异质性较大的研究，因此应谨慎看待这些结果。未来的研究应探讨个体化方法，根据产次和硬膜外麻醉状态进行分层，以确定最佳干预时机，从而完善时长指南。
