Department of Environmental and Occupational Health, Program in Public Health, University of California, Irvine, CA, USA.
Department of Environmental and Occupational Health, Program in Public Health, University of California, Irvine, CA, USA; Institute of Medical Information, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Environ Int. 2023 Mar;173:107824. doi: 10.1016/j.envint.2023.107824. Epub 2023 Feb 13.
Significant mortality and morbidity in pregnant women and their offspring are linked to premature rupture of membranes (PROM). Epidemiological evidence for heat-related PROM risk is extremely limited. We investigated associations between acute heatwave exposure and spontaneous PROM.
We conducted this retrospective cohort study among mothers in Kaiser Permanente Southern California who experienced membrane ruptures during the warm season (May-September) from 2008 to 2018. Twelve definitions of heatwaves with different cut-off percentiles (75th, 90th, 95th, and 98th) and durations (≥ 2, 3, and 4 consecutive days) were developed using the daily maximum heat index, which incorporates both daily maximum temperature and minimum relative humidity in the last gestational week. Cox proportional hazards models were fitted separately for spontaneous PROM, term PROM (TPROM), and preterm PROM (PPROM) with zip codes as the random effect and gestational week as the temporal unit. Effect modification by air pollution (i.e., PM and NO), climate adaptation measures (i.e., green space and air conditioning [AC] penetration), sociodemographic factors, and smoking behavior was examined.
In total, we included 190,767 subjects with 16,490 (8.6%) spontaneous PROMs. We identified a 9-14% increase in PROM risks associated with less intense heatwaves. Similar patterns as PROM were found for TPROM and PPROM. The heat-related PROM risks were greater among mothers exposed to a higher level of PM during pregnancy, under 25 years old, with lower education and household income level, and who smoked. Even though climate adaptation factors were not statistically significant effect modifiers, mothers living with lower green space or lower AC penetration were at consistently higher heat-related PROM risks compared to their counterparts.
Using a rich and high-quality clinical database, we detected harmful heat exposure for spontaneous PROM in preterm and term deliveries. Some subgroups with specific characteristics were more susceptible to heat-related PROM risk.
胎膜早破（PROM）与孕妇及其后代的高死亡率和高发病率有关。与热相关的 PROM 风险的流行病学证据极其有限。我们调查了急性热浪暴露与自发性 PROM 之间的关联。
我们在 Kaiser Permanente Southern California 进行了这项回顾性队列研究，该研究纳入了 2008 年至 2018 年温暖季节（5 月至 9 月）期间发生胎膜破裂的母亲。使用每日最大热指数（将每日最大温度和最小相对湿度纳入最后一个妊娠周）制定了 12 种不同截断百分比（第 75 百分位、90 百分位、95 百分位和 98 百分位）和持续时间（≥2、3 和 4 天）的热浪定义。分别使用邮政编码作为随机效应，妊娠周作为时间单位，使用 Cox 比例风险模型对自发性 PROM、足月胎膜早破（TPROM）和早产胎膜早破（PPROM）进行拟合。还检验了空气污染（即 PM 和 NO）、气候适应措施（即绿地和空调[AC]渗透率）、社会人口因素和吸烟行为的效应修饰作用。
总共纳入了 190767 名受试者，其中 16490 名（8.6%）发生自发性 PROM。我们发现，与强度较低的热浪相比，PROM 风险增加了 9-14%。TPROM 和 PPROM 也出现了类似的模式。在怀孕期间暴露于更高水平 PM 的母亲、年龄在 25 岁以下、教育程度和家庭收入水平较低以及吸烟的母亲中，热相关的 PROM 风险更高。尽管气候适应因素不是统计学上显著的效应修饰因素，但与同龄人相比，绿地或 AC 渗透率较低的母亲始终面临更高的热相关 PROM 风险。
使用丰富和高质量的临床数据库，我们在早产和足月分娩中检测到自发性 PROM 的有害热暴露。具有特定特征的一些亚组对热相关的 PROM 风险更敏感。
