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The Environment and Reproductive Health (EARTH) Study: A Prospective Preconception Cohort



Details

  • Personal Author:
  • Corporate Authors:
    Harvard School of Public Health. Environment and Reproductive Health Study Team
  • Description:
    STUDY QUESTION: Do environmental exposures, diet and lifestyle factors impact reproductive and pregnancy outcomes among subfertile couples attending a fertility clinic? SUMMARY ANSWER: Environmental chemicals exposure in men and women were associated with reduced fertility and a higher risk of adverse outcomes, whereas some dietary factors improved the probability of successful reproductive outcomes. WHAT IS KNOWN ALREADY: Accumulating epidemiologic evidence has shown associations of environmental chemicals and nutritional factors with reproductive and pregnancy outcomes. However, few studies have been designed to assess these factors simultaneously, and even fewer have collected such data among both men and women in the preconception period. Furthermore, early and sensitive reproductive endpoints (e.g. fertilization, implantation, biochemical pregnancy loss) are largely unobservable in population-based designs. STUDY DESIGN SIZE, DURATION: The Environment and Reproductive Health (EARTH) Study is an ongoing prospective preconception cohort designed to investigate the impact of environmental, nutritional and lifestyle factors in both women and men on fertility and pregnancy outcomes. The study has been ongoing since 2004 and has recruited 799 women and 487 men (447 couples; 40 men joined without female partners) as of June 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS: The study recruits women aged 18-45 years and men aged 18-55 years seeking fertility evaluation and treatment at a large academic hospital fertility center. Women and men are eligible to join either independently or as a couple. Participants are followed from study entry throughout each fertility treatment cycle, once per trimester of pregnancy (for those achieving pregnancy), and up to labor and delivery, or until they discontinue treatment or withdraw from the study. The study prospectively collects a combination of biological samples (e.g. blood, urine, semen), self-reported questionnaire data (including a validated food frequency questionnaire) and medical information abstracted from fertility clinic and hospital records. MAIN RESULTS AND THE ROLE OF CHANCE: Among women in this cohort, higher urinary concentrations of some phthalate metabolites were associated with reduced oocyte yields, lower likelihood of clinical pregnancy, increased risk of pregnancy loss and lower likelihood of live birth following infertility treatment. Certain urinary phthalate metabolite concentrations among men was also associated with decreased odds of implantation and live birth. Maternal soy and folate intake significantly modified the association between bisphenol A (BPA) and IVF outcomes in women. While the EARTH Study has tested many a priori hypotheses, multiple comparisons were undertaken, and we cannot rule out the possibility that some of findings may be spurious or due to chance. LIMITATIONS REASONS FOR CAUTION: While the fertility clinic setting provides the opportunity to measure environmental exposures, diet and lifestyle factors across different windows of vulnerability and to evaluate their potential effect on critical early fertility, pregnancy and delivery outcomes, the findings may be less generalizable to naturally conceived pregnancies. WIDER IMPLICATIONS OF THE FINDINGS: The EARTH Study is one of the few cohorts designed to examine multiple windows of vulnerability, including the paternal and maternal preconception windows and the periconception and prenatal windows, in pregnancy. It is also one of the few human studies that has assessed potential interactions between environmental exposures and dietary factors. STUDY FUNDING/COMPETING INTEREST(S): The EARTH Study has been funded by the National Institute of Environmental Health Sciences since its inception in 2004. The authors declare no competing interests. TRIAL REGISTRATION NUMBER: n/a. WHAT DOES THIS MEAN FOR PATIENTS? This article reports on a cohort known as the Environment and Reproductive Health (EARTH) Study, which looks at the impact of environment, diet and lifestyle factors on human reproduction. Previous research has found links between environmental chemicals and fertility and miscarriage, but this study was wider as it looked at the effects of exposures in both men and women in the preconception period, as well diet and lifestyle and followed the participants through each stage of their fertility journey. The researchers looked at couples that had come to a large academic fertility center, and used questionnaires and samples such as blood, urine and semen to analyse what impact different exposures had on the chances of a successful pregnancy. The study found that couples with certain environmental chemicals in their samples had a lower chance of a successful outcome from treatment, but a healthy diet had a positive impact on the chances of success for both men and women. Caffeine did not make a difference for women, but it did for men. Women doing jobs that involved heavy lifting were found to have a lower chance of success. Eating fruit and vegetables with high pesticide residue was linked to lower fertility. The researchers suggest that since these couples were experiencing fertility problems they may be more sensitive to the factors examined in this study, but findings may still be of interest to others having difficulty conceiving. [Description provided by NIOSH]
  • Subjects:
  • Keywords:
  • ISSN:
    2399-3529
  • Document Type:
    Text
  • Funding:
    Grant
  • Genre:
    Journal Article
  • Place as Subject:
  • CIO:
    National Institute for Occupational Safety and Health (NIOSH)
  • Topic:
    Workplace Safety & Health
  • Location:
    North America
  • Volume:
    2018
  • Issue:
    2
  • NIOSHTIC Number:
    nn:20051734
  • Citation:
    Hum Reprod Open 2018 Feb; 2018(2):hoy001
  • Contact Point Address:
    Russ Hauser, Harvard T. H. Chan School of Public Health, 677 Huntington Ave, Boston, MA 02115, USA
  • Email:
    rhauser@hsph.harvard.edu
  • CAS Registry Number:
  • Federal Fiscal Year:
    2018
  • Performing Organization:
    Harvard University, School of Public Health, Boston, Massachusetts
  • Peer Reviewed:
    True
  • Start Date:
    20050701
  • Source Full Name:
    Human Reproduction Open
  • End Date:
    20090630
  • Collection(s):
  • Main Document Checksum:
    urn:sha-512:cd64a43ab21c73bc73d6badd32fc489f15d3a71b8c67d95aca798d8c91354abce10bea9db61da0205111c3f21d3a05763076fbd49a0dd06750bfc4935ecfb5ec
  • Download URL:
  • File Type:
    Filetype[PDF - 586.11 KB ]
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