极端环境温度暴露对早产的影响

Influence of extreme ambient temperature exposure on preterm birth

目的调查极端环境温度暴露与早产发生之间的关系。方法通过国家免费孕前优生健康检查及中国国家气象中心获得2010年至2013年湖南省衡阳市55 654名孕妇的基础资料、出生结局及环境温度暴露情况,将环境温度暴露时间分为怀孕之前3个月、怀孕第1~7周、怀孕第8~14周、怀孕第15~21周、分娩前1周和分娩前4周共6个时间段,根据各个时间段中育龄女性平均温度暴露情况的百分位数确定温度暴露水平,通过卡方检验比较不同特征人群的早产情况、用非条件Logistic回归分析不同暴露时间极端环境温度对早产的影响。结果共纳入妊娠结局为单胎活产儿的研究对象55 654名,其中早产儿4 212名(7.57%)。与中等温度(第5~95百分位数)相比,不同时期的极热环境温度暴露(>第95百分位数)可能增加早产的风险,其中以分娩前4周增加最为明显(OR=1.823,95%CI:1.562~2.127)。分娩前1周(OR:1.237,95%CI:1.073~1.426)和分娩前4周(OR=1.365,95%CI:1.187~1.570)的极端寒冷暴露(<第5百分位数)同样会增加早产的风险。此外,怀孕第15~21周的寒冷暴露可能是早产的保护因素。结论极端环境温度可能影响早产的发生,分娩前短期极热和极冷暴露均会增加早产发生的风险。

Objective To investigate the relationship between extreme ambient temperature exposure and preterm birth.Methods Basic information and birth outcomes of 55 654 pregnant women and temperature exposures in Hengyang City of Hunan Province from 2010 to 2013 were investigated from NFPCP and National Meteorological Information Center.The ambient temperature exposure period was divided into six periods,namely three months before pregnancy,1-7 weeks of pregnancy,8-14 weeks of pregnancy,15-21 weeks of pregnancy,one week before delivery and four weeks before delivery.The temperature exposure level was determined according to the percentile of the average temperature exposure of women of childbearing age in each time period.Chi-square test was used to compare the rates of preterm birth among cases of different characteristics.Unconditional Logistic regression analysis was used to compare the influence of extreme ambient temperature in different periods on preterm birth.Results A total of 55 654 singleton live births were included,among which 4 212（7.57%）were preterm birth.Compared with the moderate temperature（5-95 th percentile）,hot exposure（95 th percentile）in different periods of pregnancy increased the risk of preterm birth,and the most obvious increase was during four weeks before delivery（OR=1.823,95%CI：1.562-2.127）.Cold exposure（5 th percentile）during one week before delivery（OR=1.237,95%CI：1.073-1.426）and four weeks before delivery（OR=1.365,95%CI：1.187-1.570）also increased the risk of preterm birth.In addition,cold exposure during 15-21 weeks of pregnancy might be a protection factor of preterm birth.Conclusion Extreme ambient temperatures may affect the occurrence of preterm birth,and short-term hot and cold exposure before delivery will increase the risk of preterm birth.