Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, VA; Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, MedStar Washington Hospital Center, Washington, DC.
Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, MedStar Washington Hospital Center, Washington, DC.
Am J Obstet Gynecol. 2021 Sep;225(3):294.e1-294.e14. doi: 10.1016/j.ajog.2021.03.029. Epub 2021 Mar 31.
Maternal and neonatal outcomes associated with duration of arrest of dilation beyond 4 hours are not well known. In addition, the current definition of arrest does not consider the degree of cervical dilation (6 cm vs 7 cm vs 8 cm vs 9 cm) when arrest occurs.
We sought to examine maternal and neonatal outcomes in nulliparous women who achieved the active phase of labor according to the duration they required to achieve a cervical change of at least 1 cm (<4 hours vs 4-5.9 hours vs ≥6 hours) beginning at 6, 7, 8 and 9 cm.
This was a retrospective cohort study of nulliparous women with term singleton cephalic pregnancies in spontaneous or induced active labor (≥6 cm). To evaluate the effect of labor duration on maternal and fetal outcomes at different degrees of cervical dilation, we categorized women based on time intervals they required to achieve a cervical change of at least 1 cm after membrane rupture ("<4 hours," "4-5.9 hours," and "≥6 hours"), and we correlated each time interval with referent cervical dilation status (6 cm, 7 cm, 8 cm, and 9 cm). Maternal and neonatal outcomes were analyzed according to the duration to progress at least 1 cm starting from each degree of cervical dilation. Our primary outcome was a composite of neonatal outcomes, including intensive care unit admission, neonatal death, seizure, ventilator use, birth injury, and neonatal asphyxia. In addition, we examined maternal outcomes. Adjusted odds ratios with 95% confidence intervals were calculated, controlling for predefined covariates.
Of 31,505 nulliparous women included in this study, 13,142 (42%), 10,855 (34%), 11,761 (37%), and 17,049 (54%) reached documented cervical dilation of 6, 7, 8, and 9 cm, respectively. At cervical dilation of 6 or 7 cm, the arrest of dilation of <4 hours compared with arrest of dilation of 4 to 5.9 hours was associated with decreased risks of adverse maternal outcomes. When cervical dilation was 8 or 9 cm, arrest of dilation of <4 hours compared with arrest of dilation of 4 to 5.9 hours was associated with decreased risks of adverse maternal and neonatal outcomes. For example, women starting at a cervical dilation of 8 cm who required <4 hours to achieve a cervical change of 1 cm compared with those who required 4 to 5.9 hours had lower rates of cesarean delivery (adjusted odds ratio, 0.40; 95% confidence interval, 0.28-0.55), chorioamnionitis (adjusted odds ratio, 0.42; 95% confidence interval, 0.29-0.60), and the neonatal composite outcome (adjusted odds ratio, 0.51; 95% confidence interval, 0.36-0.72).
When cervical dilation is 6 or 7 cm, allowing arrest of dilation of ≥4 hours is reasonable because it was not associated with increased risks of adverse neonatal outcomes. When cervical dilation is 8 or 9 cm, the benefit of allowing arrest of dilation of ≥4 hours should be balanced against the risk of adverse maternal and neonatal outcomes.
目前尚不清楚扩张停滞超过 4 小时与母婴结局之间的关系。此外，目前的阻滞定义在发生阻滞时没有考虑宫颈扩张的程度（6cm、7cm、8cm 和 9cm）。
我们旨在检查初产妇在活跃期达到宫颈变化至少 1cm 所需的时间（<4 小时、4-5.9 小时、≥6 小时）与宫颈扩张程度为 6、7、8 和 9cm 时母婴结局的关系。
这是一项回顾性队列研究，纳入了足月单胎头位自发性或诱导性活跃期分娩（≥6cm）的初产妇。为了评估分娩时间对不同宫颈扩张程度母婴结局的影响，我们根据膜破裂后达到至少 1cm 宫颈变化所需的时间间隔（<4 小时、4-5.9 小时和≥6 小时）将妇女分类，并将每个时间间隔与参考宫颈扩张状态（6cm、7cm、8cm 和 9cm）相关联。根据从每个宫颈扩张程度开始至少 1cm 的进展时间，分析母婴结局。主要结局是包括新生儿重症监护病房入院、新生儿死亡、癫痫发作、呼吸机使用、分娩损伤和新生儿窒息在内的新生儿复合结局。此外，我们还检查了产妇结局。控制了预先定义的协变量后，计算了调整后的优势比及其 95%置信区间。
在这项研究中，纳入了 31505 名初产妇，其中 13142 名（42%）、10855 名（34%）、11761 名（37%）和 17049 名（54%）的宫颈分别扩张到了 6、7、8 和 9cm。在宫颈扩张到 6cm 或 7cm 时，与 4-5.9 小时相比，<4 小时的扩张阻滞与不良产妇结局的风险降低有关。当宫颈扩张到 8cm 或 9cm 时，与 4-5.9 小时相比，<4 小时的扩张阻滞与不良产妇和新生儿结局的风险降低有关。例如，与 4-5.9 小时相比，在宫颈扩张 8cm 时，需要<4 小时才能达到 1cm 宫颈变化的女性剖宫产率（调整优势比，0.40；95%置信区间，0.28-0.55）、绒毛膜羊膜炎（调整优势比，0.42；95%置信区间，0.29-0.60）和新生儿复合结局（调整优势比，0.51；95%置信区间，0.36-0.72）较低。
当宫颈扩张为 6cm 或 7cm 时，允许扩张停滞≥4 小时是合理的，因为它与新生儿不良结局的风险增加无关。当宫颈扩张为 8cm 或 9cm 时，应权衡允许扩张停滞≥4 小时的益处与母婴不良结局的风险。
