Background: Perfluorinated compounds are ubiquitous pollutants; epidemiologic data suggest they may be associated with adverse health outcomes, including subfecundity. We examined subfecundity in relation to 2 perfluorinated compounds—perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA).
Methods: This case-control analysis included 910 women enrolled in the Norwegian Mother and Child Cohort Study in 2003 and 2004. Around gestational week 17, women reported their time to pregnancy and provided blood samples. Cases consisted of 416 women with a time to pregnancy greater than 12 months, considered subfecund. Plasma concentrations of perfluorinated compounds were analyzed using liquid chromatography–mass spectrometry. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for each pollutant quartile using logistic regression. Estimates were further stratified by parity.
Results: The median plasma concentration of PFOS was 13.0 ng/mL (interquartile range [IQR] = 10.3–16.6 ng/mL) and of PFOA was 2.2 ng/mL (IQR = 1.7–3.0 ng/mL). The relative odds of subfecundity among parous women was 2.1 (95% CI = 1.2–3.8) for the highest PFOS quartile and 2.1 (1.0–4.0) for the highest PFOA quartile. Among nulliparous women, the respective relative odds were 0.7 (0.4–1.3) and 0.5 (0.2–1.2).
Conclusion: Previous studies suggest that the body burden of perfluorinated compounds decreases during pregnancy and lactation through transfer to the fetus and to breast milk. Afterward, the body burden may increase again. Among parous women, increased body burden may be due to a long interpregnancy interval rather than the cause of a long time to pregnancy. Therefore, data from nulliparous women may be more informative regarding toxic effects of perfluorinated compounds. Our results among nulliparous women did not support an association with subfecundity.
From the aDepartment of Health and Human Services, National Institute for Environmental Health Sciences, National Institutes of Health, Durham, NC; bNorwegian Institute of Public Health, Oslo, Norway; cDepartment of Chemistry, University of Oslo, Oslo, Norway; dDepartment of Public Health and Primary Health Care, University of Bergen, Bergen, Norway; and eMedical Birth Registry of Norway, the Norwegian Institute of Public Health, Bergen, Norway.
Submitted 29 March 2011; accepted 30 August 2011.
Conflicts of interest and sources of funding: Supported in part by the Intramural Research Program of the National Institutes of Health, National Institute of Environmental Health Sciences. The Norwegian Mother and Child Cohort Study is supported by the Norwegian Ministry of Health, NIH/NIEHS (contract no N01-ES-85433), NIH/NINDS (grant no. 1 UO1 NS 047537–01), and the Norwegian Research Council/FUGE (grant no. 151918/S10). The authors reported no other financial interests related to this research.
Editors' note: A commentary on this article appears on page 264.
Correspondence: Kristina W. Whitworth, National Institute of Environmental Health Sciences (NIEHS), Epidemiology Branch, P.O. Box 12233, Mail Drop A3-05, Durham, NC 27709. E-mail: email@example.com.