南非金山大学Matthew Francis Chersich团队研究了孕期遭遇高温环境与早产、低出生体重和死产风险的相关性。2020年11月4日，该研究发表在《英国医学杂志》上。

为了评估怀孕期间遭遇高温环境是否与早产、低出生体重和死产的风险增加相关，研究组在Medline和Web of Science数据库检索2019年8月之前的文献，筛选出高温环境与早产、出生体重和死产之间关联的临床研究，并进行系统评价和随机效应荟萃分析。

研究组共筛选了14880条报告和175篇论文。共纳入70项研究，涉及27个国家/地区，其中7个是中低收入国家。在47项研究的40项中，较高温度环境下的早产率高于较低温度环境。暴露因素被划分为热浪、1℃增量和温度阈值截止点。

在随机效应荟萃分析中，温度每升高1°C，早产率增加1.05倍，热浪期间早产率增加1.16倍。在28项研究的18项中，温度升高与出生体重减轻有关，且统计上的异质性很高。8项关于死胎的研究均显示温度与死胎率相关，温度每升高1°C，死胎率就会增加1.05倍。在较低社会经济群体和年龄极小或极大的女性中，温度与妊娠不良结局的相关性最大。

研究结果表明，随着全球变暖，气温上升可能对儿童健康产生重大影响。尤其在中低收入国家，风险可能最大。

附：英文原文

Title: Associations between high temperatures in pregnancy and risk of preterm birth, low birth weight, and stillbirths: systematic review and meta-analysis

Author: Matthew Francis Chersich, Minh Duc Pham, Ashtyn Areal, Marjan Mosalam Haghighi, Albert Manyuchi, Callum P Swift, Bianca Wernecke, Matthew Robinson, Robyn Hetem, Melanie Boeckmann, Shakoor Hajat

Issue&Volume: 2020/11/04

Abstract:

Objective To assess whether exposure to high temperatures in pregnancy is associated with increased risk for preterm birth, low birth weight, and stillbirth.

Design Systematic review and random effects meta-analysis.

Data sources Medline and Web of Science searched up to September 2018, updated in August 2019.

Eligibility criteria for selecting studies Clinical studies on associations between high environmental temperatures, and preterm birth, birth weight, and stillbirths.

Results 14880 records and 175 full text articles were screened. 70 studies were included, set in 27 countries, seven of which were countries with low or middle income. In 40 of 47 studies, preterm births were more common at higher than lower temperatures. Exposures were classified as heatwaves, 1°C increments, and temperature threshold cutoff points. In random effects meta-analysis, odds of a preterm birth rose 1.05-fold (95% confidence interval 1.03 to 1.07) per 1°C increase in temperature and 1.16-fold (1.10 to 1.23) during heatwaves. Higher temperature was associated with reduced birth weight in 18 of 28 studies, with considerable statistical heterogeneity. Eight studies on stillbirths all showed associations between temperature and stillbirth, with stillbirths increasing 1.05-fold (1.01 to 1.08) per 1°C rise in temperature. Associations between temperature and outcomes were largest among women in lower socioeconomic groups and at age extremes. The multiple temperature metrics and lag analyses limited comparison between studies and settings.

Conclusions Although summary effect sizes are relatively small, heat exposures are common and the outcomes are important determinants of population health. Linkages between socioeconomic status and study outcomes suggest that risks might be largest in low and middle income countries. Temperature rises with global warming could have major implications for child health.

DOI: 10.1136/bmj.m3811

Source: https://www.bmj.com/content/371/bmj.m3811