Longitudinal Investigation of Fertility and the Environment

生命研究的目的是评估环境因素（广义上包括生活方式因素）对人类生殖和发育的影响。生命研究符合尤尼斯·肯尼迪·施莱弗国家儿童健康和人类发展研究所的使命，该研究所的使命包括开展基础、临床和流行病学研究，重点关注与人类生殖和发育有关的因素和过程，从而确保出生的健康婴儿能够在不受身体或精神残疾影响的情况下充分发挥成人潜力。

The purpose of the LIFE Study is to assess the impact of environmental factors, broadly defined to include lifestyle factors, on human reproduction and development. The LIFE Study is consistent with the mission of the Eunice Kennedy Shriver National Institute of Child Health and Human Development that includes conducting basic, clinical and epidemiologic research focusing on factors and processes associated with human reproduction and development thereby, ensuring the birth of healthy infants capable of reaching full adult potential unimpaired by physical or mental disabilities. This study is assessing the relation between select environmental factors and human fecundity and fertility, particularly in the context of lifestyle. 501 couples discontinuing contraception for purposes of becoming pregnant were recruited from 16 targeted counties in Michigan and Texas. Couples completed baseline interviews and standardized anthropometric assessments and were prospectively followed for up to 12 months attempting pregnancy. Pregnant women were followed until delivery. Couples provided blood and urine samples at baseline, and men provided semen samples and women saliva samples for the analysis of semen quality and stress biomarkers, respectively. Select blood metals (lead and cadmium), serum organochlorine pollutants (PCBs and PFCs), short lived (e.g.,parabens, phenols, phthalates) chemicals and acute exposure ambient air pollution species were found to be associated with couple fecundity as measured by a longer time required for pregnancy. Male chemical concentrations were observed to be associated with greater reduction in fecundity. Other persistent chemicals such as PFCs were associated with select semen quality endpoints as were other short lived chemicals such as specific phthalates and UV-type BP filters. In a substudy, phytoestrogens were not meaningfully associated with menstrual cycle length but were associated with menstrual regularity among women with self-reported regular cycles (Levine et al. 2020; accepted 2019).