Methodology for establishing a population-based birth cohort focusing on couple fertility and children's development, the Upstate KIDS Study

Paediatr Perinat Epidemiol. 2014 May;28(3):191-202. doi: 10.1111/ppe.12121. Epub 2014 Mar 25.


Background: Critical data gaps remain regarding infertility treatment and child development. We assessed the utility of a birth certificate registry for developing a population cohort aimed at answering such questions.

Methods: We utilised the Upstate New York livebirth registry (n = 201,063) to select births conceived with (n = 4024) infertility treatment or exposed infants, who were then frequency-matched by residence to a random sample of infants conceived without (n = 14,455) treatment or unexposed infants, 2008-10. Mothers were recruited at 2-4 months postpartum and queried about their reproductive histories, including infertility treatment for comparison with birth certificate data. Overall, 1297 (32%) mothers of exposed and 3692 of unexposed (26%) infants enrolled.

Results: Twins represented 22% of each infant group. The percentage of infants conceived with/without infertility treatment was similar whether derived from the birth registry or maternal report: 71% none, 16% drugs or intrauterine insemination, and 14% assisted reproductive technologies (ART). Concordant reporting between the two data sources was 93% for no treatment, 88% for ART, and 83% for fertility drugs, but differed by plurality. Exposed infants had slightly (P < 0.01) earlier gestations than unexposed infants (38.3 ± 2.8 and 38.7 ± 2.7 weeks, respectively) based upon birth certificates but not maternal report (38.7 ± 2.7 and 38.7 ± 2.9, respectively). Conversely, mean birthweight was comparable using birth certificates (3157 ± 704 and 3194 ± 679 g, respectively), but differed using maternal report (3167 ± 692 and 3224 ± 661, respectively P < 0.05).

Conclusions: The birth certificate registry is a suitable sampling framework as measured by concordance with maternally reported infertility treatment. Future efforts should address the impact of factors associated with discordant reporting on research findings.

Keywords: assisted reproductive technologies; children; fecundity; in vitro fertilization; infertility.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Birth Certificates*
  • Birth Rate
  • Child
  • Child Development*
  • Child, Preschool
  • Family Characteristics
  • Female
  • Fertility*
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Multiple Birth Offspring / statistics & numerical data*
  • New York / epidemiology
  • Population Surveillance
  • Pregnancy
  • Pregnancy Outcome
  • Registries
  • Reproductive Techniques, Assisted / statistics & numerical data*
  • Surveys and Questionnaires
  • Twins