Huang Qiqi, Pan Xiong-Fei, Yan Shijiao, Sun Zhonghan, Lai Yuwei, Ye Yixiang, Yuan Jiaying, Lv Chuanzhu, Wang Rixing, Song Xingyue
School of Public Health, Hainan Medical University, Haikou, Hainan, 570100, China.
Section of Epidemiology and Population Health & Department of Gynecology and Obstetrics, Ministry of Education Key Laboratory of Birth Defects and Related Diseases of Women and Children & National Medical Products Administration Key Laboratory for Technical Research On Drug Products In Vitro and In Vivo Correlation, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.
BMC Public Health. 2025 Jan 24;25(1):299. doi: 10.1186/s12889-025-21403-5.
Due to climate change, the frequency and intensity of heat waves and other extreme weather events are rapidly increasing. Compared to the general population, pregnant women and fetuses are increasingly vulnerable to the effects of extreme temperatures and are associated with the occurrence of adverse birth outcomes, including preterm birth (PTB). However, its risk of preterm birth is currently uncertain. The objective of the research is to examine the effect of ambient temperature on PTB in pregnant women.
This study included 6,850 pregnant women from the Tongji-Shuangliu Birth Cohort. Meteorological data for Chengdu through the European Centre for Medium-Range Weather Forecasts. The main exposure assessment was conducted during eight different exposure windows, including the first three months of pregnancy, 7 weeks periods during the first two trimesters, throughout pregnancy, 1-week preceding delivery, and 4 weeks preceding delivery. The effect of environmental temperature on PTB during different exposure windows was assessed using the logistic regression based on the percentile of the mean temperature in different exposure cycles. Additionally, the lagged effect of environmental temperature on preterm births throughout the study period was analyzed using a distributed lag non-linear model.
Among the 6850 pregnant women, 301 (4.4%) were diagnosed with PTB. Compared to mild temperature (10th to 90th percentile), exposure to extreme cold (< 10th percentile) temperature during the 4 weeks preceding delivery (RR = 2.45, 95% CI:1.11,5.40) and throughout pregnancy (RR = 3.85, 95% CI:1.56,9.53) increased the risk of PTB. In addition, hot temperature (> 90th percentile) at 4 weeks preceding delivery (RR = 0.33, 95% CI:0.13,0.86) and 22-28 weeks of pregnancy (RR = 0.25, 95% CI:0.11,0.59), and cold exposure at 1-week preceding delivery(RR = 0.51, 95% CI:0.27,0.96), reduced risk of PTB. In the lagged model, compared with 18° C (50th percentile), 7 °C (10th percentile) had the strongest effect on lag day 21 and lag 22 (RR = 1.20, 95% CI:1.03,1.40; RR = 1.20, 95% CI:1.03,1.39). A temperature of 27° C (90th percentile) was protective for PTB from the 22nd day of lag(RR = 0.86, 95% CI:0.75,0.99).
This study indicates that high temperature may be a protective factor for PTB, while low temperature may be a risk factor, with an obvious lag effect.
由于气候变化，热浪和其他极端天气事件的频率和强度正在迅速增加。与普通人群相比，孕妇和胎儿越来越容易受到极端温度的影响，并与不良出生结局的发生有关，包括早产（PTB）。然而，其早产风险目前尚不确定。本研究的目的是探讨环境温度对孕妇早产的影响。
本研究纳入了来自同济-双流出生队列的6850名孕妇。通过欧洲中期天气预报中心获取成都的气象数据。主要暴露评估在八个不同的暴露窗口进行，包括妊娠的前三个月、孕早期和孕中期的7周时间段、整个孕期、分娩前1周以及分娩前4周。基于不同暴露周期的平均温度百分位数，使用逻辑回归评估不同暴露窗口期间环境温度对早产的影响。此外，使用分布滞后非线性模型分析整个研究期间环境温度对早产的滞后效应。
在6850名孕妇中，301名（4.4%）被诊断为早产。与温和温度（第10至90百分位数）相比，分娩前4周（RR = 2.45，95% CI：1.11，5.40）和整个孕期（RR = 3.85，95% CI：1.56，9.53）暴露于极端寒冷（<第10百分位数）温度会增加早产风险。此外，分娩前4周（RR = 0.33，95% CI：0.13，0.86）和妊娠22 - 28周（RR = 0.25，95% CI：0.11，0.59）的高温（>第90百分位数），以及分娩前1周的寒冷暴露（RR = 0.51，95% CI：0.27，0.96），会降低早产风险。在滞后模型中，与18°C（第50百分位数）相比，7°C（第10百分位数）对滞后第21天和第22天的影响最强（RR = 1.20，95% CI：1.03，1.40；RR = 1.20，95% CI：1.03，1.39）。27°C（第90百分位数）的温度从滞后第22天起对早产具有保护作用（RR = 0.86，95% CI：0.75，0.99）。
本研究表明，高温可能是早产的保护因素，而低温可能是危险因素，且具有明显的滞后效应。
