Analysis of preterm birth trends among advanced maternal-age women in Haidian District, Beijing from 2013 to 2022
10.3760/cma.j.cn113903-20240329-00226
- VernacularTitle:2013年至2022年北京市海淀区高龄产妇早产流行特征
- Author:
Xiaoxuan ZOU
1
;
Jiaxin LI
;
Yinzhu ZHAO
;
Yanmin YIN
;
Ying YANG
Author Information
1. 北京市海淀区妇幼保健院妇幼信息科，北京 100086
- Publication Type:Journal Article
- Keywords:
Advanced maternal age women;
Preterm birth;
Trend;
Joinpoint regression;
Interrupted time series
- From:
Chinese Journal of Perinatal Medicine
2025;28(3):226-232
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze the trends of preterm birth among women of advanced maternal age in Haidian District, Beijing from 2013 to 2022.Methods:A retrospective analysis was conducted on the birth registration data in Haidian District, Beijing, from January 2013 to December 2022, focusing on the records of women aged ≥35 who delivered between 22 and 44 weeks of gestation. The Joinpoint regression model was used to analyze the time trends of preterm birth rates among women of advanced maternal age in the Haidian District. Interrupted time series (ITS) analysis was applied to quantitatively evaluate the transient and long-term effects of China's universal two-child policy on the preterm birth rate among women of advanced maternal age.Results:(1) A total of 70 640 birth registration records from 68 587 women were finally included. The number of women giving birth peaked between 2016 and 2018 (8 158, 9 906, and 8 914 cases, respectively). The proportion of permanent residents in Beijing gradually decreased from 53.7% (2 175/4 049) in 2013 to 42.0% (4 160/9 906) in 2017 and then increased to over 98% between 2019 and 2022 [98.8% (7 828/7 925), 99.1% (6 283/6 340), 99.3% (5 970/6 014), and 99.5% (6 371/6 404), respectively]. (2) Among the 68 587 women, 57 339 (83.6%) were delivered at tertiary hospitals, and 35 496 (51.8%) were delivered by cesarean section. The proportion of multiple births increased slowly from 2.4% (236/9 906) in 2017 to 3.5% (225/6 404) in 2022. From 2013 to 2015, primiparous women accounted for the majority. Subsequently, the proportion of multiparous women increased annually, reaching 71.6% (6 385/8 914) in 2018 before gradually decreasing to 56.2% (3 600/6 404) in 2022. (3) A total of 70 640 live births were delivered. The highest number of deliveries was in 2017, with 10 139 cases. From 2013 to 2022, 36 995 male infants and 33 645 female infants were born, with preterm birth rates of 10.6% (3 914/36 995) and 9.4% (3 123/33 645), respectively. (4) Among the 70 640 infants, there were 124 extremely preterm infants (0.2%), 773 very preterm infants (1.1%), and 6 140 late preterm infants (8.7%), accounting for 1.8%, 11.0%, and 87.3% of all preterm infants (7 037 cases), respectively. (5) The optimal fitting results of Joinpoint regression indicated that the preterm birth rate showed a declining trend from 2013 to 2017 ( APC=－4.4%, 95% CI: -13.0% to -0.2%); with 2017 as the turning point, the preterm birth rate exhibited an upward trend from 2017 to 2022 ( APC=4.5%, 95% CI: 1.6% to 13.0%). (6) The results of ITS analysis revealed that the preterm birth rate instantly decreased by 0.79% ( β2=－0.79, P=0.026) in the month when the universal two-child policy took effect. In comparison, it increased by an average of 0.03% per month ( β3=0.07, P=0.001) after the implementation of the policy. After adjusting for the proportion of multiple births, the preterm birth rate significantly decreased before the policy took effect ( β1=－0.06, P=0.003), but increased by an average of 0.01% per month ( β3=0.07, P<0.001) after the policy took effect. There was no statistical significance in the transient impact of the policy on the preterm birth rate in this district ( β2=0.80, P=0.145). Conclusions:From 2013 to 2022, the preterm birth rates among women of advanced maternal age in Haidian District exhibit a "V"-shaped pattern with the implementation of the two-child policy as the turning point. It is necessary to continue strengthening maternal health care for women of advanced maternal age and ensure the targeted provision of related services to address the issue of increased preterm birth rates following the enforcement of the two-child policy.
