Extreme heat events and fertility: a national study

项目概要/摘要 热浪和其他极端天气事件的频率和强度正在迅速增加， 气候变化，预计在未来几十年内只会加剧。虽然极端高温的危害 人类健康，包括对怀孕和分娩结果的不利影响， 关于环境温度和人类生育能力的已知信息。人口统计学研究表明炎热的天气 导致出生率在8到10个月后显著下降，但这种关联的驱动因素尚不清楚。 长期以来，动物文献也记录了高血压引起的母体体温过高与高脂血症之间的联系。 环境温度和生育力降低，主要通过对卵母细胞发育的影响介导 然而，热应激是否对女性卵泡发育有类似的影响尚不清楚。 拟议的研究旨在利用现有的大型数据库和强大的方法来测试 最重要的假设是，在卵泡形成过程中暴露于极端高温的妇女将有 卵母细胞质量和胚胎发育受损，植入失败的风险较高， 活产。我们还假设，在持续时间较长的热事件后，将观察到更强的影响 和更大的强度，影响将因时间、空间和个人水平的属性而异。为了验证这一 假设，我们将利用来自200多万个非供体辅助生殖技术（ART）周期的数据 从1996年到2016年在美国发起，作为国家ART监测系统的一部分收集。 国家气象数据将使用高分辨率陆地数据的公开数据进行整合 同化系统-一个全国性的近地面温度和湿度的1公里分辨率数据集， 1981-2016.接受抗逆转录病毒治疗的妇女是研究极端高温 通过对卵巢的不利影响来影响生育能力，因为我们可以确定极端高温的确切时期 直接观察在夫妇中永远不会观察到的早期生殖结果 在没有帮助的情况下怀孕。通过将我们的分析限制在使用供体精子和冷冻胚胎的周期中， 转移，我们还可以独特地检查卵泡发生期间极端热暴露对ART的影响。 结果独立于男性伴侣和植入窗口期间的热暴露。鉴于 气温上升和越来越多的妇女推迟到35岁才生育的平行趋势 随着年龄的增长，了解极端高温对生育能力的影响变得越来越重要。我们 调查结果可以为有针对性的法规、政策、公共卫生预警系统和干预措施提供重要信息， 最终目标是减少不孕症和早孕丢失。

PROJECT SUMMARY/ABSTRACT The frequency and intensity of heatwaves and other extreme weather events is increasing rapidly owing to climate change and is only projected to escalate in the coming decades. While the hazards of extreme heat on human health are widely recognized, including adverse effects on pregnancy and birth outcomes, little is known regarding ambient temperature and human fertility. Demographic studies suggest that hot weather causes a significant decline in birth rates 8 to 10 months later, yet the drivers of this association are unclear. The animal literature has also long documented a link between maternal hyperthermia induced by high ambient temperatures and reduced fertility, largely mediated through effects on oocyte developmental capacity; however, whether heat stress has a similar impact on follicular development in women is less clear. The proposed research seeks to use a large existing database and robust methodological approaches to test the overarching hypothesis that women exposed to extreme heat during folliculogenesis will have compromised oocyte quality and embryo development, higher risk of implantation failure, and lower probability of live birth. We also hypothesize that stronger effects will be observed following heat events of longer duration and greater intensity and that effects will vary by temporal-, spatial-, and individual-level attributes. To test this hypothesis, we will utilize data from over 2 million non-donor assisted reproductive technology (ART) cycles initiated in the US from 1996 to 2016 that are collected as part of the National ART Surveillance System. National weather data will be integrated using publicly available data from the High Resolution Land Data Assimilation System– a national 1 km resolution dataset of near-surface temperature and humidity that spans 1981-2016. Women undergoing ART represent an ideal setting to investigate the hypothesis that extreme heat affects fertility through adverse effects on the ovary as we can determine exact periods of extreme heat exposure and directly observe early reproductive outcomes that would never be observed in couples conceiving without assistance. By restricting our analysis to cycles using donor sperm and frozen embryo transfers, we can also uniquely examine the effects of extreme heat exposure during folliculogenesis on ART outcomes independent from heat exposures to the male partner and during the implantation window. Given the parallel trends of rising temperatures and the increasing number of women delaying motherhood until 35 years and older, understanding the effects of extreme heat on fertility is becoming increasingly important. Our findings can greatly inform targeted regulations, policies, public health warning systems, and interventions with the ultimate goal of reducing infertility and early pregnancy loss.