Do stressful life events during pregnancy modify associations between phthalates and anogenital distance in newborns?
- DOI
- Language of the publication
- English
- Date
- 2019-07-19
- Type
- Article
- Author(s)
- Arbuckle, Tye E.
- MacPherson, Susan
- Barrett, Emily
- Muckle, Gina
- Séguin, Jean R.
- Foster, Warren G.
- Sathyanarayana, Sheela
- Dodds, Linda
- Fisher, Mandy
- Agarwal, Amisha
- Monnier, Patricia
- Walker, Mark
- Fraser, William D.
- Publisher
- Elsevier
Abstract
Anogenital distance (AGD) has been used as a marker of fetal androgen action to identify endocrine disrupting chemicals. A US study (TIDES) has reported that the association between some phthalates and reduced AGD in males was only apparent in sons of mothers reporting no stressful life events (SLEs) during pregnancy. The objective of the current study was to examine the potential modifying effect of SLEs and their subjective impact on associations between prenatal phthalates and AGD. First trimester urines from the MIREC Study were analysed for phthalate metabolites and AGD was measured in neonates. Post-delivery, the women answered questions on SLEs during the pregnancy. Women reporting 1 or more SLEs during pregnancy were considered a “higher stressor” group, whereas women reporting no SLEs or who reported a SLE that was perceived as not at all stressful were considered a “lower stressor” group. Multivariable linear regression models were fit stratified by stressor group. Maternal stressor, AGD and phthalates results were available for 153 females and 147 males. A summary measure of androgen-disrupting phthalates (Σ AD) was associated with significantly longer AGDs in females from the higher stressor group. These effect sizes were increased when the perceived impact was restricted to moderately or very much stressful. In males, all phthalates were associated with longer anopenile distance (APD), regardless of stressor group; however, higher Σ AD was associated with significantly longer APD in the lower stressor group. In contrast to the TIDES study, we did not observe shorter AGDs in male infants prenatally exposed to di-(2-ethylhexyl) phthalates, regardless of maternal stressor level. In conclusion, we were unable to replicate the findings of the TIDES study, but did find some evidence that prenatal SLEs may modify associations between phthalates and female AGD. Further research with other populations and measures of prenatal stress may shed more light on whether prenatal stress is an important effect modifier of associations between phthalates (or other chemicals) and anogenital distance.
Plain language summary
"Health Canada helps to protect the health of Canadians by assessing and managing the risks associated with exposure to environmental chemicals. Phthalates are chemicals found in the environment that are suspected of affecting foetal development. One US study reported that prenatal exposure to phthalates was associated with a shorter anogenital distance, but only if the woman reported no stressful life events during pregnancy. Anogenital distance (AGD) is the distance between the anus and penis in infant boys and between the anus and clitoris in infant girls and is an accepted metric of prenatal development. The objective of this study was to test whether the US result could be replicated in the Maternal-Infant Research on Environmental Chemicals (MIREC) Study. Phthalate concentrations were measured in urine of pregnant women. Women reporting one or more stressful life events during pregnancy were considered the “high stressor” group, whereas women reporting no events were considered a “lower stressor” group. Statistical models were fit to examine the relationship between the phthalate concentrations and AGD stratified by stressor group, while controlling for potential confounders. Maternal stressor and phthalate results were available for 128 females and 125 males. Among mothers in the higher stressor group, prenatal levels of mono-ethyl phthalate and the sum of low molecular weight (LMW) phthalates were associated with longer AGD in female offspring. Only for LMW was an association observed with shorter AGD in males but only among mothers in the higher stressor group. In conclusion, these results did not agree with those of the US study. The inconsistencies in results between studies suggest that this issue is yet to be resolved. Further research with other populations and measures of prenatal stress may shed some light on whether prenatal stress is an important effect modifier of associations between phthalates (or other chemicals) and AGD."
Subject
- Health,
- Health and safety