Polybrominated diphenyl ethers and incident pregnancy loss: The LIFE Study

Background: Polybrominated diphenyl ethers (PBDEs) have not been studied in relation to incident pregnancy loss in human populations, despite their ubiquitous exposure and purported reproductive toxicity. Objectives: To investigate the association between preconception serum PBDE concentrations and incident pregnancy loss. Methods: A preconception cohort of 50.1 couples was followed while trying to become pregnant, and for whom serum concentrations of 10 PBDE congeners were measured using gas chromatography-high resolution mass spectrometry. Pregnancy was prospectively identified as a positive home pregnancy test on the day of expected menstruation. Incident pregnancy loss was defined for 344 singleton pregnancies as a conversion to a negative home pregnancy test, menses, or clinical diagnosis depending upon gestational age. Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for individual and summed PBDEs and incident pregnancy loss, adjusting for relevant covariates and male partners' information. In sensitivity analyses, inverse probability weighting was used to account for couples not becoming pregnant and, thereby, not at risk for loss. Results: The incidence of prospectively observed pregnancy loss was 28%, and the serum concentrations of PBDE congeners in females were consistently associated with a higher hazard of incident pregnancy loss. Specifically, statistically significant hazard ratios (HRs) for incident pregnancy loss were observed for lower brominated PBDE congeners: 17 (HR 1.23; CI: 1.07-1.42), 28 (HR 1.25; CI: 1.03-1.52), 66 (HR 1.23; CI: 1.07-1.42), and homolog triBDE (HR: 1.25; CI: 1.05-1.49). Findings were robust to various model specifications explored in sensitivity analyses. Conclusions: Maternal preconception serum concentrations of specific PBDE congeners may increase the hazard of incident pregnancy.