Hormones play critical roles in facilitating pregnancy progression and the onset of parturition. Several classes of environmental contaminants, including fine particulate matter (PM_2.5) and ambient temperature, have been shown to alter hormone biosynthesis or activity. However, epidemiologic research has not considered PM_2.5 in relation to a broader range of steroid hormones, particularly in pregnant women. Using metabolomics data collected within 20–40 weeks of gestation in an ethnically diverse pregnancy cohort study, we identified 42 steroid hormones that we grouped into five classes (pregnenolone, androgens, estrogens, progestin, and corticosteroids) based on their biosynthesis type. We found that exposure to PM_2.5 during the pre-conception and early prenatal periods was associated with higher maternal androgen concentrations in late pregnancy. We also detected a positive association between early pregnancy PM_2.5 exposure and maternal pregnenolone levels and a marginal positive association between early pregnancy PM_2.5 exposure and progestin levels. When considering each hormone metabolite individually, we found positive associations between early pregnancy PM_2.5 exposure and five steroids, two of which survived multiple comparison testing: 11beta-hydroxyandrosterone glucuronide (a pregnenolone steroid) and adrosteroneglucuronide (a progestin steroid). None of the steroid classes were statistically significant associated with ambient temperature. In sex-stratified analyses, we did not detect any sex differences in our associations. This is the first study showing that exposure to fine particulate matter during the pre-conception and early prenatal periods can lead to altered steroid adaptation during the state of pregnancy, which has been shown to have potential consequences on maternal and child health.

激素在促进妊娠进展和分娩开始方面发挥着关键作用。几类环境污染物，包括细颗粒物 (PM _2.5 ) 和环境温度，已被证明会改变激素生物合成或活性。然而，流行病学研究并未考虑 PM _2.5与更广泛的类固醇激素的关系，特别是在孕妇中。利用在一项种族多样化妊娠队列研究中妊娠 20-40 周内收集的代谢组学数据，我们鉴定了 42 种类固醇激素，根据其生物合成类型将其分为五类（孕烯醇酮、雄激素、雌激素、孕激素和皮质类固醇）。我们发现，暴露于 PM _2.5受孕前和产前早期与妊娠后期母体雄激素浓度较高有关。我们还发现，早孕 PM _2.5暴露与母体孕烯醇酮水平之间存在正相关，早孕 PM _2.5暴露与孕激素水平之间存在边际正相关。当单独考虑每种激素代谢物时，我们发现早孕 PM _{2.5之间呈正相关}暴露和五种类固醇，其中两种通过了多重比较测试：11β-羟基雄甾酮葡萄糖醛酸（一种孕烯醇酮类固醇）和雄激素葡萄糖醛酸（一种孕激素类固醇）。没有任何类固醇类别与环境温度相关具有统计显着性。在性别分层分析中，我们没有发现我们的关联存在任何性别差异。这是第一项研究表明，在受孕前和产前早期接触细颗粒物可能会导致怀孕期间类固醇适应的改变，这已被证明对孕产妇和儿童健康产生潜在影响。