Preterm Birth in China Between 2015 and 2016.

Abstract

<i>Objectives.</i> To describe the incidence, risk factors, and potential causes of preterm birth (PTB) in China between 2015 and 2016.<i>Methods.</i> The China Labor and Delivery Survey was a population-based multicenter study conducted from 2015 to 2016. We assigned each birth a weight based on the sampling frame. We calculated the incidence of PTB and the multivariable logistic regression, and we used 2-step cluster analysis to examine the relationships between PTB and maternal, fetal, and placental conditions.<i>Results.</i> The weighted nationwide incidence of PTB was 7.3% of all births and 6.7% of live births at 24 or more weeks of gestation. Of the PTBs, 70.5% were born after 34 weeks and 42.7% were iatrogenic. Nearly two thirds of all preterm births were attributable to maternal, fetal, or placental conditions, and one third had unknown etiology.<i>Conclusions.</i> This study provided information on the incidence of PTB in China and identified several factors associated with PTB. The high frequency of iatrogenic PTB calls for a careful assessment and prudent management of such pregnancies, as PTB has short- and long-term health consequences.