Ananth CV, et al. - In this retrospective cohort analysis, researchers evaluated changes in the gestational age distribution among spontaneous and clinician-initiated deliveries between 2006 and 2013 and associated changes in neonatal mortality. Findings revealed that there was a decline in spontaneous deliveries related to an overall decline in neonatal mortality in the US. Neonatal mortality at declined at 39 to 40 weeks, although clinician-initiated deliveries increased at that gestation.

Methods

• From August to October 2017, data analysis was performed.
• Main outcomes and measures were 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 evaluated from log-linear Poisson regression models with robust variance, adjusted for confounders.

Results

• According to the findings, among 22 million births, 12,493,531 (56.7%) were spontaneous and 9,557,815 (43.3%) were clinician-initiated 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 spontaneous 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 clinician-initiated deliveries.
• It was observed that overall neonatal mortality rates declined from 1.8 to 1.3 per 1,000 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 spontaneous deliveries.
• It was noted that overall mortality rates remained unchanged (2.1 to 2.2 per 1000 live births) among clinician-initiated deliveries.
• Data reported that 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.