title: The association between nonylphenols and sexual hormones levels among pregnant women: a cohort study in Taiwan.
abstract: BACKGROUND
  Nonylphenol (NP) has been proven as an endocrine disrupter and had the ability to interfere with the endocrine system. Though the health effects of NP on pregnant women and their fetuses are sustained, these negative associations related to the mechanisms of regulation for estrogen during pregnancy need to be further clarified. The objective of this study is to explore the association between maternal NP and hormonal levels, such as estradiol, testosterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH), and progesterone.
  
  
  METHODS
  A pregnant women cohort was established in North Taiwan between March and December 2010. Maternal urine and blood samples from the first, second, and third trimesters of gestation were collected. Urinary NP concentration was measured by high-performance liquid chromatography coupled with fluorescent detection. A mixed-effects model using a generalised estimating equation (GEE) was applied to assess the associations between maternal NP concentration and plasma hormones throughout the three trimesters.
  
  
  RESULTS
  In total, 162 singleton pregnant women completed this study through delivery. The geometric mean of creatinine-adjusted urinary NP concentrations were 4.27, 4.21, and 4.10 µg/g cre. in the first, second, and third trimesters respectively. A natural log-transformation of urinary NP concentrations were significantly associated with LH in the GEE model (β = -0.23 mIU/ml, p<0.01).
  
  
  CONCLUSIONS
  This perspective cohort study demonstrates that negative association occurs between maternal NP exposure and plasma LH levels. The estrogen-mimic effect of NP might influence the negative feedback on LH during pregnancy.
authors.affiliation: Institute of Environmental and Occupational Health Sciences, School of Medicine, National Yang Ming University, Taipei, Taiwan; Department of OBS & GYN, Cathay General Hospital, Taipei, Taiwan.
authors.forename: Chia-Huang
authors.initials: CH
authors.lastname: Chang
authors.affiliation: Department of OBS & GYN, Cathay General Hospital, Taipei, Taiwan; School of Medicine, Fu Jen Catholic University, Taipei, Taiwan.
authors.forename: Ming-Song
authors.initials: MS
authors.lastname: Tsai
authors.affiliation: Department of Endocrinology and Metabolism, Cathay General Hospital, Taipei, Taiwan.
authors.forename: Ching-Ling
authors.initials: CL
authors.lastname: Lin
authors.affiliation: Department of Pediatrics, Cathay General Hospital, Taipei, Taiwan.
authors.forename: Jia-Woei
authors.initials: JW
authors.lastname: Hou
authors.affiliation: Department of Obstetrics and Gynecology, College of Medicine, Chang Gung University Genomic Medicine Research Core Laboratory (GMRCL), Chang Gung Memorial Hospital, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
authors.forename: Tzu-Hao
authors.initials: TH
authors.lastname: Wang
authors.affiliation: Institute of Environmental and Occupational Health Sciences, School of Medicine, National Yang Ming University, Taipei, Taiwan.
authors.forename: Yen-An
authors.initials: YA
authors.lastname: Tsai
authors.affiliation: Institute of Environmental and Occupational Health Sciences, School of Medicine, National Yang Ming University, Taipei, Taiwan.
authors.forename: Kai-Wei
authors.initials: KW
authors.lastname: Liao
authors.affiliation: Department of Occupational Safety and Health, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: I-Fang
authors.initials: IF
authors.lastname: Mao
authors.affiliation: Institute of Environmental and Occupational Health Sciences, School of Medicine, National Yang Ming University, Taipei, Taiwan.
authors.forename: Mei-Lien
authors.initials: ML
authors.lastname: Chen
mesh_terms: D000328:Adult; D015331:Cohort Studies; D052244:Endocrine Disruptors / Q000009:adverse effects* / Q000652:urine; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006801:Humans; D018811:Maternal Exposure / Q000009:adverse effects*; D008875:Middle Aged; D010636:Phenols / Q000009:adverse effects* / Q000652:urine; D011247:Pregnancy; D012307:Risk Factors; D013624:Taiwan; D055815:Young Adult
chemical_list: D052244:Endocrine Disruptors; D012739:Gonadal Steroid Hormones; D010636:Phenols; C025256:nonylphenol