Behrens Jessica A, Greer Danielle M, Kram Jessica J F, Schmit Eric, Forgie Marie M, Salvo Nicole P
Aurora Health Care, Department of Obstetrics and Gynecology, Aurora Sinai Medical Center, Milwaukee, WI, United States.
Aurora Health Care, Aurora UW Medical Group and Center for Urban Population Health, Aurora Sinai Medical Center, Milwaukee, WI, United States.
Eur J Obstet Gynecol Reprod Biol. 2019 Jan;232:22-29. doi: 10.1016/j.ejogrb.2018.10.038. Epub 2018 Oct 28.
Retained placenta is the most common second-trimester delivery complication. As the optimal third stage of labor duration remains undefined, complications associated with retained placentas are difficult to study.
OBJECTIVE(S): To determine the optimal third stage of labor duration in second-trimester deliveries based on estimates of time-specific probabilities of placental delivery, placental intervention, and postpartum complication.
We retrospectively studied adult women with singleton second-trimester vaginal deliveries. We identified third stage of labor duration, placental delivery method (spontaneous vs. manual/operative intervention), and indication for intervention. Postpartum complication was examined as a composite outcome. Differences among groups defined by delivery method and postpartum complication were tested using parametric and nonparametric tests. Probability curves describing the time-specific probabilities of placental delivery were derived using lifetable methods with group differences tested using the log-rank test. Probability of placental intervention and complication by time to placental delivery were examined using logistic regression with adjustment for confounders and other predictors.
We identified 215 second-trimester placental deliveries (77% spontaneous, 23% intervention). Overall, 27% experienced postpartum complication, primarily hemorrhage (91%). Complication rates differed significantly between spontaneous placental deliveries (16%) and interventions (61%, P < 0.01). Both placental intervention and postpartum complication were strongly associated with longer time to placental delivery. Spontaneous placental deliveries occurred earlier than deliveries requiring intervention (P < 0.01). At 2 h, placental delivery rates were 93% in spontaneous deliveries and 39% in those requiring intervention. The overall postpartum complication rate for spontaneous placental deliveries (16%) was used as the threshold of tolerable risk and the criterion for placental intervention. Adjusted probability curves for deliveries of average gestational age (21.6 weeks) suggested that most patients (63.9%) may not require intervention until approximately 2 h following fetal delivery. Patients with PPROM would require intervention by 34 min, and those with intrapartum fever or delivery EBL ≥500 mL would already exceed the risk threshold at fetal delivery.
Our study suggests that an optimal third stage of labor duration of approximately 2 h maximizes probability of spontaneous delivery and minimizes complication risk. Timing of intervention may be further individualized for patients based on maternal characteristics and intrapartum conditions.
胎盘残留是孕中期分娩最常见的并发症。由于最佳的第三产程时长仍未明确，与胎盘残留相关的并发症难以研究。
基于胎盘娩出、胎盘干预及产后并发症的特定时间概率估计，确定孕中期分娩的最佳第三产程时长。
我们回顾性研究了单胎孕中期经阴道分娩的成年女性。我们确定了第三产程时长、胎盘娩出方式（自然娩出与手法/手术干预）及干预指征。将产后并发症作为一个综合结局进行检查。使用参数检验和非参数检验来检验由分娩方式和产后并发症定义的组间差异。使用寿命表法得出描述胎盘娩出特定时间概率的概率曲线，并使用对数秩检验来检验组间差异。使用逻辑回归分析胎盘娩出时间与胎盘干预及并发症的概率，并对混杂因素和其他预测因素进行校正。
我们确定了215例孕中期胎盘娩出（77%自然娩出，23%干预）。总体而言，27%的患者出现产后并发症，主要是出血（91%）。自然胎盘娩出组（16%）和干预组（61%，P < 0.01）的并发症发生率差异显著。胎盘干预和产后并发症均与胎盘娩出时间延长密切相关。自然胎盘娩出比需要干预的分娩发生得更早（P < 0.01）。在2小时时，自然分娩的胎盘娩出率为93%，需要干预的分娩为39%。自然胎盘娩出的总体产后并发症发生率（16%）被用作可接受风险的阈值和胎盘干预的标准。平均孕周（21.6周）分娩的校正概率曲线表明，大多数患者（63.9%）在胎儿娩出后约2小时前可能不需要干预。胎膜早破患者在34分钟时需要干预，而产时发热或分娩时估计失血量≥500 mL的患者在胎儿娩出时已经超过了风险阈值。
我们的研究表明，约2小时左右的最佳第三产程时长可使自然分娩概率最大化，并使并发症风险最小化。可根据产妇特征和产时情况进一步对患者的干预时机进行个体化调整。
