title: First trimester phthalate exposure and anogenital distance in newborns.
abstract: OBJECTIVE
  Is first trimester phthalate exposure associated with anogenital distance (AGD), a biomarker of prenatal androgen exposure, in newborns?
  
  
  CONCLUSIONS
  Concentrations of diethylhexyl phthalate (DEHP) metabolites in first trimester maternal urine samples are inversely associated with AGD in male, but not female, newborns.
  
  
  BACKGROUND
  AGD is a sexually dimorphic measure reflecting prenatal androgen exposure. Prenatal phthalate exposure has been associated with shorter male AGD in multiple animal studies. Prior human studies, which have been limited by small sample size and imprecise timing of exposure and/or outcome, have reported conflicting results.
  
  
  METHODS
  The Infant Development and the Environment Study (TIDES) is a prospective cohort study of pregnant women recruited in prenatal clinics in San Francisco, CA, Minneapolis, MN, Rochester, NY and Seattle, WA in 2010-2012. Participants delivered 787 infants; 753 with complete data are included in this analysis.
  
  
  METHODS
  Any woman over 18 years old who was able to read and write English (or Spanish in CA), who was <13 weeks pregnant, whose pregnancy was not medically threatened and who planned to deliver in a study hospital was eligible to participate. Analyses include all infants whose mothers provided a first trimester urine sample and who were examined at or shortly after birth. Specific gravity (SpG) adjusted concentrations of phthalate metabolites in first trimester urine samples were examined in relation to genital measurements. In boys (N = 366), we obtained two measures of anogenital distance (AGD) (anoscrotal distance, or AGDAS and anopenile distance, AGDAP) as well as penile width (PW). In girls (N = 373), we measured anofourchette distance (AGDAF) and anoclitoral distance (AGDAC). We used multivariable regression models that adjusted for the infant's age at exam, gestational age, weight-for-length Z-score, time of day of urine collection, maternal age and study center.
  
  
  RESULTS
  Three metabolites of DEHP were significantly and inversely associated with both measures of boys' AGD. Associations (β, 95% confidence interval (CI)) between AGDAS and (log10) SpG-adjusted phthalate concentrations were: -1.12 (-2.16, -0.07) for mono-2-ethylhexyl phthalate (MEHP), -1.43, (-2.49, -0.38) for mono-2-ethyl-5-oxohexyl phthalate (MEOHP), and -1.28 (-2.29, -0.27) for mono-2-ethyl-5-hydroxyhexyl (MEHHP). Associations were of similar magnitude for AGDAP. Associations were weaker and not statistically significant for PW. No other phthalate metabolites were associated with any genital measurement in boys. No phthalate metabolites were associated with either AGD measure in girls.
  
  
  CONCLUSIONS
  Exposure assessment was based on a single first trimester urine sample, which may have introduced exposure misclassification. In addition, significant between-center differences suggest that this measurement is difficult to standardize.
  
  
  CONCLUSIONS
  Our findings are consistent with multiple rodent studies and most human studies which were far smaller. The data we report here suggest that even at current low levels, environmental exposure to DEHP can adversely affect male genital development resulting in reproductive tract changes that may impact reproductive health later in life. These findings have important implications for public policy since most pregnant women are exposed to this ubiquitous chemical.
  
  
  BACKGROUND
  Funding for TIDES was provided by the following grants from the National Institute of Environmental Health Sciences: R01ES016863-04 and R01 ES016863-02S4. The authors report no conflict of interest.
authors.affiliation: Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA shanna.swan@mssm.edu.
authors.forename: S H
authors.initials: SH
authors.lastname: Swan
authors.affiliation: Department of Pediatrics, University of Washington, Seattle, WA, USA Seattle Children's Research Institute, Seattle, WA, USA.
authors.forename: S
authors.initials: S
authors.lastname: Sathyanarayana
authors.affiliation: Department of Obstetrics and Gynecology, University of Rochester, Rochester, NY, USA.
authors.forename: E S
authors.initials: ES
authors.lastname: Barrett
authors.affiliation: Department of Occupational Medicine, University of California San Francisco, San Francisco, CA, USA.
authors.forename: S
authors.initials: S
authors.lastname: Janssen
authors.affiliation: Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: F
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Epidemiology & Community Health, University of Minnesota, Minneapolis, MN, USA.
authors.forename: R H N
authors.initials: RH
authors.lastname: Nguyen
authors.affiliation: Department of Medicine, University of Minnesota, Minneapolis, MN, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Redmon
mesh_terms: D000328:Adult; D001003:Anal Canal / Q000033:anatomy & histology / Q000187:drug effects*; D000728:Androgens / Q000009:adverse effects; D015415:Biomarkers; D001835:Body Weight; D004051:Diethylhexyl Phthalate / Q000633:toxicity* / Q000652:urine*; D005260:Female; D005836:Genitalia, Female / Q000033:anatomy & histology / Q000187:drug effects; D005837:Genitalia, Male / Q000033:anatomy & histology / Q000187:drug effects; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D018811:Maternal Exposure; D015999:Multivariate Analysis; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011446:Prospective Studies; D012737:Sex Factors
chemical_list: D000728:Androgens; D015415:Biomarkers; D004051:Diethylhexyl Phthalate
keywords: anogenital distance; environmental chemicals; phthalate syndrome; phthalates; prenatal development