University of Montreal Hospital Research Centre, 900 Saint Denis St, Montreal, Quebec H2X 0A9, Canada; Institut national de santé publique du Québec, 190 Cremazie Blvd E, Montreal, Quebec H2P 1E2, Canada; Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, 1020 Pine Avenue W, Montreal, Quebec H3A 1A2, Canada.
National Collaborating Centre for Environmental Health, British Columbia Centre for Disease Control, 601 West Broadway, Vancouver, British Columbia V5Z 4C2, Canada.
Environ Int. 2018 Feb;111:295-300. doi: 10.1016/j.envint.2017.11.004. Epub 2017 Nov 14.
Outdoor heat increases the risk of preterm birth and stillbirth, but the association with placental abruption has not been studied. Placental abruption is a medical emergency associated with major morbidity and mortality in pregnancy. We determined the relationship between ambient temperature and risk of placental abruption in warm seasons.
We performed a case-crossover analysis of 17,172 women whose pregnancies were complicated by placental abruption in Quebec, Canada from May to October 1989-2012. The main exposure measure was the maximum temperature reached during the week before abruption. We computed odds ratios (OR) and 95% confidence intervals (CI) for the association of temperature with placental abruption, adjusted for humidity and public holidays. We assessed whether associations were stronger preterm or at term, or varied with maternal age, parity, comorbidity and socioeconomic status.
Compared with 15°C, a maximum weekly temperature of 30°C was associated with 1.07 times the odds of abruption (95% CI 0.99-1.16). When the timing of abruption was examined, the associations were significantly stronger at term (OR 1.12, 95% CI 1.02-1.24) than preterm (OR 0.96, 95% CI 0.83-1.10). Relationships were more prominent at term for women who were younger than 35years old, nulliparous or socioeconomically disadvantaged, but did not vary with comorbidity. Associations were stronger within 1 and 5days of abruption. Temperature was not associated with preterm abruption regardless of maternal characteristics.
Elevated temperatures in warm seasons may increase the risk of abruption in women whose pregnancies are near or at term. Pregnant women may be more sensitive to heat and should consider preventive measures such as air conditioning and hydration during hot weather.
户外高温会增加早产和死胎的风险，但尚未研究其与胎盘早剥的关系。胎盘早剥是一种医疗急症，与妊娠期间的主要发病率和死亡率有关。我们确定了温暖季节环境温度与胎盘早剥风险之间的关系。
我们对 1989 年至 2012 年 5 月至 10 月期间在加拿大魁北克因胎盘早剥而怀孕的 17172 名妇女进行了病例交叉分析。主要暴露测量指标是早剥前一周达到的最高温度。我们计算了温度与胎盘早剥之间的关联的比值比（OR）和 95%置信区间（CI），调整了湿度和公共假期的影响。我们评估了关联是否在早产或足月时更强，或者是否因母亲年龄、产次、合并症和社会经济地位而异。
与 15°C 相比，每周最高温度为 30°C 时，胎盘早剥的几率增加 1.07 倍（95%CI 0.99-1.16）。当检查胎盘早剥的时间时，足月时的关联明显强于早产（OR 1.12，95%CI 1.02-1.24），而早产时的关联较弱（OR 0.96，95%CI 0.83-1.10）。对于年龄小于 35 岁、初产妇或社会经济地位较低的妇女，这种关系更为明显，但与合并症无关。在早剥发生后 1 天和 5 天内，关联更强。无论产妇特征如何，高温均与早产早剥无关。
温暖季节的高温可能会增加接近或足月的孕妇发生胎盘早剥的风险。孕妇可能对高温更为敏感，因此在炎热天气中应考虑采取空调和补水等预防措施。
