title: Epidemiologic tools to study the influence of environmental factors on fecundity and pregnancy-related outcomes.
abstract: Adverse pregnancy outcomes entail a large health burden for the mother and offspring; a part of it might be avoided by better understanding the role of environmental factors in their etiology. Our aims were to review the assessment tools to characterize fecundity troubles and pregnancy-related outcomes in human populations and their sensitivity to environmental factors. For each outcome, we reviewed the possible study designs, main sources of bias, and their suggested cures. In terms of study design, for most pregnancy outcomes, cohorts with recruitment early during or even before pregnancy allow efficient characterization of pregnancy-related events, time-varying confounders, and in utero exposures that may impact birth outcomes and child health. Studies on congenital anomalies require specific designs, assessment of anomalies in medical pregnancy terminations, and, for congenital anomalies diagnosed postnatally, follow-up during several months after birth. Statistical analyses should take into account environmental exposures during the relevant time windows; survival models are an appropriate approach for fecundity, fetal loss, and gestational duration/preterm delivery. Analysis of gestational duration could distinguish pregnancies according to delivery induction (and possibly pregnancy-related conditions). In conclusion, careful design and analysis are required to better characterize environmental effects on human reproduction.
authors.affiliation: Abbreviations: PROM, premature rupture of the fetal membranes; TTP, time to pregnancy.
authors.forename: Rémy
authors.initials: R
authors.lastname: Slama
authors.forename: Ferran
authors.initials: F
authors.lastname: Ballester
authors.forename: Maribel
authors.initials: M
authors.lastname: Casas
authors.forename: Sylvaine
authors.initials: S
authors.lastname: Cordier
authors.forename: Merete
authors.initials: M
authors.lastname: Eggesbø
authors.forename: Carmen
authors.initials: C
authors.lastname: Iniguez
authors.forename: Mark
authors.initials: M
authors.lastname: Nieuwenhuijsen
authors.forename: Claire
authors.initials: C
authors.lastname: Philippat
authors.forename: Sylvie
authors.initials: S
authors.lastname: Rey
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Vandentorren
authors.forename: Martine
authors.initials: M
authors.lastname: Vrijheid
mesh_terms: D001724:Birth Weight / Q000187:drug effects; D015984:Causality; D000013:Congenital Abnormalities / Q000453:epidemiology* / Q000209:etiology; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis / Q000706:statistics & numerical data*; D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000009:adverse effects / Q000032:analysis*; D015340:Epidemiologic Research Design; D005260:Female; D005298:Fertility / Q000187:drug effects; D005322:Premature Rupture of Fetal Membranes / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D063868:Patient Outcome Assessment; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology* / Q000209:etiology; D011256:Pregnancy Outcome / Q000453:epidemiology; D047928:Premature Birth / Q000453:epidemiology / Q000209:etiology; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology*
chemical_list: D004785:Environmental Pollutants
keywords: birth weight; cohort studies; congenital abnormalities; environment; fecundity; fetal membranes, premature rupture; pregnancy; preterm birth