Department of Epidemiology and Biostatics, School of Public Health, Peking University, Beijing, China.
Yunnan Population and Family Planning Research Institute, Yunnan, China.
Front Public Health. 2023 Jun 20;11:1101283. doi: 10.3389/fpubh.2023.1101283. eCollection 2023.
The progression of global warming and increase in instances of extreme weather have received considerable attention. We conducted a cohort study on women of childbearing age in Yunnan Province, examined the association between ambient temperature and humidity on preterm birth and evaluated the effects of extreme weather during early pregnancy and before parturition on preterm birth.
We conducted a population-based cohort study on women of childbearing age 18-49 years who participated in National Free Preconception Health Examination Project (NFPHEP) in Yunnan Province from January 1, 2010, to December 31, 2018. Meteorological data, namely daily average temperature (°C) and daily average relative humidity (%), were obtained from China National Meteorological Information Center. Four exposure windows were explored: 1 week of pregnancy, 4 weeks of pregnancy, 4 weeks before delivery, and 1 week before delivery. We used a Cox proportional hazards model and adjusted the potential risk factors for preterm birth to obtain the effects of exposure to temperature and humidity on preterm birth among the stages of pregnancy.
At 1 week of pregnancy and at 4 weeks of pregnancy, the association between temperature and preterm birth was U-shaped. The correlation between relative humidity and the risk of preterm birth was n-type at 1 week of pregnancy. The correlation between preterm birth and temperature and relative humidity at 4 weeks before delivery and at 1 week before delivery is J-shaped. Low temperature and low humidity were protective factors against preterm birth, whereas high temperature and high humidity were risk factors for preterm birth.The effects of high temperature and extremely high temperature were the strongest at 4 weeks before delivery, with HRs of 1.417 (95% CI: 1.362-1.474) and 1.627 (95% CI: 1.537-1.722), respectively. The effects of extremely low humidity and low humidity were strongest at 1 week before delivery, with HRs of 0.681 (95% CI: 0.609-0.761) and 0.696 (95% CI: 0.627-0.771), respectively.
Temperature and relative humidity affect preterm birth differently for each pregnancy stage. The effects of meteorological factors on pregnancy outcomes such as premature birth should not be ignored.
全球变暖的加剧和极端天气事件的增加引起了广泛关注。我们对云南省育龄妇女进行了队列研究，考察了环境温度和湿度与早产的关系，并评估了孕早期和分娩前极端天气对早产的影响。
我们对 2010 年 1 月 1 日至 2018 年 12 月 31 日期间参加云南省国家免费孕前优生健康检查项目（NFPHEP）的 18-49 岁育龄妇女进行了基于人群的队列研究。气象数据（日平均温度（°C）和日平均相对湿度（%））来自中国国家气象信息中心。我们探讨了四个暴露窗口：怀孕 1 周、怀孕 4 周、分娩前 4 周和分娩前 1 周。我们使用 Cox 比例风险模型，并调整了早产的潜在危险因素，以获得温度和湿度在妊娠各阶段对早产的影响。
在怀孕 1 周和怀孕 4 周时，温度与早产之间呈 U 型关系。在怀孕 1 周时，相对湿度与早产风险呈 N 型关系。在分娩前 4 周和分娩前 1 周时，温度和相对湿度与早产的关系呈 J 型。低温和低湿度是早产的保护因素，而高温和高湿度是早产的危险因素。在分娩前 4 周时，高温和极高温度的影响最强，HR 分别为 1.417（95%CI：1.362-1.474）和 1.627（95%CI：1.537-1.722）。在分娩前 1 周时，极低湿度和低湿度的影响最强，HR 分别为 0.681（95%CI：0.609-0.761）和 0.696（95%CI：0.627-0.771）。
温度和相对湿度对每个妊娠阶段的早产有不同的影响。气象因素对早产等妊娠结局的影响不应忽视。
