Department of Health Policy and Management, Joseph L. Mailman School of Public Health, Columbia University, New York, New York.
Department of Obstetrics and Gynecology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York.
JAMA Pediatr. 2018 Oct 1;172(10):949-957. doi: 10.1001/jamapediatrics.2018.1792.
Preterm and postterm deliveries have declined since 2005 in the United States, but the association between these changes and neonatal mortality remains unknown.
To estimate changes in the gestational age distribution among spontaneous and clinician-initiated deliveries between 2006 and 2013 and associated changes in neonatal mortality.
DESIGN, SETTING, AND PARTICIPANTS: A retrospective cohort analysis was conducted of 22 million singleton live births without major malformations in the United States from 2006 to 2013. Data analysis was performed from August to October 2017.
Changes in gestational age distribution among spontaneous and clinician-initiated deliveries at extremely preterm (20-27 weeks), very preterm (28-31 weeks), moderately preterm (32-33 weeks), late preterm (34-36 weeks), early term (37-38 weeks), term (39-40), late term (41 weeks), and postterm (42-44 weeks) gestations and changes in neonatal mortality rates at less than 28 days between 2006 and 2013. These changes were estimated from log-linear Poisson regression models with robust variance, adjusted for confounders.
Among 22 million births, 12 493 531 (56.7%) were spontaneous and 9 557 815 (43.3%) were clinician-initiated deliveries. Among spontaneous deliveries, the proportion of births at 20 to 27, 28 to 31, 32 to 33, 34 to 36, and 37 to 38 weeks declined. Among clinician-initiated deliveries, the proportion of births at 34 to 36 and 37 to 38 weeks declined and the proportion at 39 to 40 weeks increased. Among spontaneous deliveries, overall neonatal mortality rates declined from 1.8 to 1.3 per 1000 live births, mainly at 20 to 27 weeks (adjusted annual decline, 1%; 95% CI, -2% to -1%) and 28 to 31 weeks (adjusted annual decline, 6%; 95% CI, -8% to -5%). Among clinician-initiated deliveries, overall mortality rates remained unchanged (2.1 to 2.2 per 1000 live births). However, mortality rates declined (0.6 to 0.5 per 1000 live births) at 39 to 40 weeks by 1% (95% CI, -3% to -0.4%) annually, adjusted for confounders.
In the United States, there was a decline in spontaneous deliveries associated with an overall decline in neonatal mortality. Although clinician-initiated deliveries increased at 39 to 40 weeks, neonatal mortality at that gestation declined.
自 2005 年以来，美国的早产和过期分娩有所下降，但这些变化与新生儿死亡率之间的关联尚不清楚。
评估 2006 年至 2013 年间自发性和临床医生启动分娩的胎龄分布变化以及由此导致的新生儿死亡率变化。
设计、地点和参与者：对 2006 年至 2013 年间美国无重大畸形的 2200 万例单胎活产进行了回顾性队列分析。数据分析于 2017 年 8 月至 10 月进行。
在极早产（20-27 周）、非常早产（28-31 周）、中度早产（32-33 周）、晚期早产（34-36 周）、早期足月（37-38 周）、足月（39-40 周）、晚期足月（41 周）和过期（42-44 周）妊娠中，自发性和临床医生启动分娩的胎龄分布变化，以及 2006 年至 2013 年间小于 28 天的新生儿死亡率变化。这些变化是通过稳健方差的对数线性泊松回归模型估计的，并根据混杂因素进行了调整。
在 2200 万例分娩中，12493531 例（56.7%）为自发性分娩，9557815 例（43.3%）为临床医生启动分娩。在自发性分娩中，20 至 27 周、28 至 31 周、32 至 33 周、34 至 36 周和 37 至 38 周的分娩比例下降。在临床医生启动的分娩中，34 至 36 周和 37 至 38 周的分娩比例下降，而 39 至 40 周的分娩比例上升。在自发性分娩中，新生儿死亡率总体从每 1000 例活产 1.8 例降至 1.3 例，主要是在 20 至 27 周（调整后的年下降率为 1%；95%CI，-2%至-1%）和 28 至 31 周（调整后的年下降率为 6%；95%CI，-8%至-5%）。在临床医生启动的分娩中，死亡率保持不变（每 1000 例活产 2.1 例至 2.2 例）。然而，在调整混杂因素后，39 至 40 周的死亡率每年下降 0.6%至 0.5%（每 1000 例活产下降 1%；95%CI，-3%至-0.4%）。
在美国，自发性分娩的减少与新生儿死亡率的总体下降有关。尽管临床医生启动的分娩在 39 至 40 周增加，但该胎龄的新生儿死亡率下降。
