Urinary phthalate metabolites in relation to preterm birth in Mexico city.
BACKGROUND
Rates of preterm birth have been rising over the past several decades. Factors contributing to this trend remain largely unclear, and exposure to environmental contaminants may play a role.


OBJECTIVE
We investigated the relationship between phthalate exposure and preterm birth.


METHODS
Within a large Mexican birth cohort study, we compared third-trimester urinary phthalate metabolite concentrations in 30 women who delivered preterm (< 37 weeks of gestation) with those of 30 controls (> or = 37 weeks of gestation).


RESULTS
Concentrations of most of the metabolites were similar to those reported among U.S. females, although in the present study mono-n-butyl phthalate (MBP) concentrations were higher and monobenzyl phthalate (MBzP) concentrations lower. In a crude comparison before correcting for urinary dilution, geometric mean urinary concentrations were higher for the phthalate metabolites MBP, MBzP, mono(3-carboxylpropyl) phthalate, and four metabolites of di(2-ethyl-hexyl) phthalate among women who subsequently delivered preterm. These differences remained, but were somewhat lessened, after correction by specific gravity or creatinine. In multivariate logistic regression analysis adjusted for potential confounders, elevated odds of having phthalate metabolite concentrations above the median level were found.


CONCLUSIONS
We found that phthalate exposure is prevalent among this group of pregnant women in Mexico and that some phthalates may be associated with preterm birth.
Meeker
John D
JD
Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA. meekerj@umich.edu
Hu
Howard
H
Cantonwine
David E
DE
Lamadrid-Figueroa
Hector
H
Calafat
Antonia M
AM
Ettinger
Adrienne S
AS
Hernandez-Avila
Mauricio
M
Loch-Caruso
Rita
R
Téllez-Rojo
Martha María
MM
D000328:Adult; D016022:Case-Control Studies; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D018811:Maternal Exposure; D008800:Mexico; D010795:Phthalic Acids / Q000652:urine*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D047928:Premature Birth / Q000652:urine*; D012307:Risk Factors; D055815:Young Adult
D010795:Phthalic Acids