Day-specific probabilities of clinical pregnancy based on two studies with imperfect measures of ovulation.

Published

Journal Article

Two studies have related the timing of sexual intercourse (relative to ovulation) to day-specific fecundability. The first was a study of Catholic couples practising natural family planning in London in the 1950s and 1960s and the second was of North Carolina couples attempting to become pregnant in the early 1980s. The former identified ovulation based on the ovulatory shift in the basal body temperature, while the latter used urinary assays of hormones. We use a statistical model to correct for error in identifying ovulation and to re-estimate the length of the fertile window and day-specific fecundabilities. We estimate the same 6-day fertile interval in both studies after controlling for error. After adjusting for error both data sets showed the highest estimate of the probability of pregnancy on the day prior to ovulation and both fell close to zero after ovulation. Given that the fertile interval is before ovulation, methods that anticipate ovulation by several days (such as the assessment of cervical mucus) would be particularly useful for couples who want to time their intercourse either to avoid or facilitate conception.

Full Text

Duke Authors

Cited Authors

  • Dunson, DB; Baird, DD; Wilcox, AJ; Weinberg, CR

Published Date

  • July 1999

Published In

Volume / Issue

  • 14 / 7

Start / End Page

  • 1835 - 1839

PubMed ID

  • 10402400

Pubmed Central ID

  • 10402400

Electronic International Standard Serial Number (EISSN)

  • 1460-2350

International Standard Serial Number (ISSN)

  • 0268-1161

Digital Object Identifier (DOI)

  • 10.1093/humrep/14.7.1835

Language

  • eng