A pilot study published in the journal Fertility and Sterility suggests that exposure to certain harmful chemicals called phthalates may lead to an increased burden of fibroids, uterine tumors that can cause heavy bleeding, pain, infertility, and other serious reproductive problems.
2019 Study Abstract
Objectives
To examine the association between phthalate exposure and two measures of uterine fibroid burden: diameter of largest fibroid and uterine volume.
Design
Pilot, cross-sectional study.
Setting
Academic medical center.
Patient(s)
Fifty-seven premenopausal women undergoing either hysterectomy or myomectomy for fibroids.
Intervention(s)
None.
Main Outcome Measure(s)
The diameter of the largest fibroid and uterine dimensions were abstracted from medical records. Spot urine samples were analyzed for 14 phthalate biomarkers using mass spectrometry. We estimated associations between fibroid outcomes and individual phthalate metabolites, sum of di(2-ethylhexyl) phthalate metabolites (∑DEHP), and a weighted sum of anti-androgenic phthalate metabolites (∑AA Phthalates) using linear regression, adjusting for age, race/ethnicity, and body mass index. Fibroid outcomes were also examined dichotomously (divided at the median) using logistic regression.
Results
Most women were of black ethnicity, overweight or obese, and college educated. In multivariable models, higher levels of mono-hydroxyisobutyl phthalate, monocarboxyoctyl phthalate, monocarboxynonyl phthalate, mono(2-ethylhexyl) phthalate, mono(2-ethyl-5-hydroxyhexyl phthalate) (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), ∑DEHP, and ∑AA Phthalates were positively associated with uterine volume. Associations were most pronounced for individual DEHP metabolites (MEHHP, MEOHP, MECPP), ∑DEHP, and ∑AA Phthalates. For example, a doubling in ∑DEHP and ∑AA Phthalates was associated with 33.2% (95% confidence interval 6.6–66.5) and 26.8% (95% confidence interval 2.2–57.4) increase in uterine volume, respectively. There were few associations between phthalate biomarkers and fibroid size.
Conclusions
Exposure to some phthalate biomarkers was positively associated with uterine volume, which further supports the hypothesis that phthalate exposures may be associated with fibroid outcomes. Additional studies are needed to confirm these relationships.
The George Washington University press release.