Impact of female age and nulligravidity on fecundity in an older reproductive age cohort

Capsule:
Women experience a significant reduction in fecundity and an increase in the probability of infertility in the late thirties. At any age >30 years, women, who have never conceived before, have a lower probability of conception.

Authors:
Anne Z. Steiner, M.D., M.P.H., Anne Marie Z. Jukic, Ph.D.

Volume 105, Issue 6, Pages 1584-1588

Abstract:

Objective:
To provide female age-related estimates of fecundity and incidence of infertility by history of prior pregnancy among women 30–44 years of age.

Design:
Prospective, time-to-pregnancy cohort study.

Setting:
Not applicable.

Patient(s):
Women, between 30 and 44 years of age, attempting to conceive for ≤3 months, and no known history of infertility, polycystic ovarian syndrome (PCOS), or endometriosis.

Intervention(s):
Not applicable.

Main Outcome Measure(s):
Fecundability and incidence of infertility.

Result(s):
Compared to women aged 30–31 years, fecundability was reduced by 14% in women 34–35 years of age (fecundability ratio [FR] 0.86, 95% confidence interval [CI] 0.68–1.08), 19% in women 36–37 years of age (FR 0.81, 95% CI 0.60–1.08, 30% in women 38–39 years of age (FR 0.70, 95% CI 0.48–1.01), 53% in women 40–41 years of age (FR 0.47, 95% CI 0.28–0.78), and 59% in women 42–44 years of age (FR 0.39, 95% CI 0.16–0.93). Fecundability did not differ between women aged 30–31 years and 32–33 years. In general, fecundability and cumulative probability of pregnancy was lower for women who had never had a prior pregnancy.

Conclusion(s):
Women experience a significant reduction in fecundity and increase in the probability of infertility in their late thirties. At any age >30 years, women who have never conceived have a lower probability of achieving a pregnancy.

Clinical Trial Registration Number:
NCT01028365.

  • Talita Honorato

    Dear authors : very nice work. And I was wondering about the nulligravid group of women with faster decline of fertility. Could that group include unkown infertile women? And this could not have happened to the group with a previous pregnancy. But still, it does not explain the higher fecundity rate for age range 32-33. Do you have comments on it?

    • Anne Steiner

      Yes. I think this is likely the cause. A woman, who has previously conceived likely has patent fallopian tubes and a partner with good sperm. This may not be true of a woman, who has never conceived before. Also, most women in their thirties have been sexually active. Contraception is not perfect. Thus women, who have not conceived, may inherently have underlying fertility issues.

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