Extreme heat events and fertility: a national study

项目摘要/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，原因是 气候变化，预计未来几十年只会升级。在酷热的危害下 人类健康得到了广泛的认可，包括对怀孕和分娩结果的不利影响，但很少被认可 已知环境温度和人类生育能力。人口统计学研究表明，炎热的天气 导致8到10个月后出生率的显著下降，但这种联系的驱动因素尚不清楚。 动物文献也早就证明了高热引起的母体体温过高之间的联系 环境温度和生育力下降，主要是通过影响卵母细胞发育来调节的 然而，热应激是否对女性的卵泡发育有类似的影响还不太清楚。 拟议的研究试图使用现有的大型数据库和可靠的方法论方法来测试 最重要的假设是，在卵泡发生过程中暴露在极端高温下的女性将有 卵母细胞质量和胚胎发育受损，植入失败的风险较高，几率较低 活产的人。我们还假设，在持续时间较长的高温事件之后将观察到更强的影响 而且强度更大，这种影响将因时间、空间和个人层面的属性而异。为了测试这一点 假设，我们将利用200多万个非捐赠者辅助生殖技术(ART)周期的数据 1996年至2016年在美国发起，作为国家艺术监督系统的一部分收集。 国家气象数据将使用高分辨率土地数据中的公开数据进行整合 同化系统-国家1公里分辨率的近地表温度和湿度数据集 1981-2016年。接受艺术治疗的女性是研究极端高温假说的理想环境 通过对卵巢的不利影响来影响生育，因为我们可以确定极端高温的确切时间段 并直接观察夫妇中永远不会观察到的早期生殖结果 没有帮助就怀孕了。通过将我们的分析限制在使用捐赠者精子和冷冻胚胎的周期 此外，我们还可以独一无二地检测卵泡发生过程中极端高温暴露对ART的影响。 结果不受男性伴侣和植入窗内热暴露的影响。给定 气温上升和越来越多的妇女将母亲推迟到35岁的趋势是平行的 随着年龄的增长，了解极端高温对生育的影响变得越来越重要。我们的 调查结果可以为有针对性的法规、政策、公共卫生警告系统和干预措施提供极大的信息 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.