Changes with age in the level and duration of fertility in the menstrual cycle.

Published

Journal Article

BACKGROUND:Most analyses of age-related changes in fertility cannot separate effects due to reduced frequency of sexual intercourse from effects directly related to ageing. Information on intercourse collected daily through each menstrual cycle provides the data for estimating day-specific probabilities of pregnancy for specific days relative to ovulation, and these estimates allow unconfounded analysis of ageing effects. METHODS:A total of 782 healthy couples using natural family planning methods contributed prospective data on 5860 menstrual cycles. Day of ovulation was based on basal body temperature measurements. Estimates of day-specific probabilities of pregnancy and the length of the fertile window were compared across age groups. RESULTS:Nearly all pregnancies occurred within a 6 day fertile window. There was no evidence for a shorter fertile window in older men or women. On average, the day-specific probabilities of pregnancy declined with age for women from the late 20s onward, with probabilities of pregnancy twice as high for women aged 19-26 years compared with women aged 35-39 years. Controlling for age of the woman, fertility was significantly reduced for men aged >35 years. CONCLUSIONS:Women's fertility begins to decline in the late 20s with substantial decreases by the late 30s. Fertility for men is less affected by age, but shows significant decline by the late 30s.

Full Text

Duke Authors

Cited Authors

  • Dunson, DB; Colombo, B; Baird, DD

Published Date

  • May 2002

Published In

Volume / Issue

  • 17 / 5

Start / End Page

  • 1399 - 1403

PubMed ID

  • 11980771

Pubmed Central ID

  • 11980771

Electronic International Standard Serial Number (EISSN)

  • 1460-2350

International Standard Serial Number (ISSN)

  • 0268-1161

Digital Object Identifier (DOI)

  • 10.1093/humrep/17.5.1399

Language

  • eng