Fertility by Age Calculator

Female fertility declines with age because women are born with all the eggs they will ever have. Egg quantity and quality both decline over time. The monthly fecundity rate (probability of conception per cycle) is approximately 25–28% for women in their early 20s, 20–23% at age 30, 15–18% at 33–35, 10–14% at 37–38, 6–10% at 40, and 2–6% at 42–44. After 45, conception with one's own eggs is uncommon but not impossible.

Based on published research and ACOG estimates: age 20–24 ≈ 25–28% per cycle; age 25–29 ≈ 22–25%; age 30–32 ≈ 20%; age 33–34 ≈ 18%; age 35–37 ≈ 14–15%; age 38–39 ≈ 10%; age 40–42 ≈ 6%; age 43–44 ≈ 4%; age 45–47 ≈ 2%; age 48+ ≈ 1%. These are population averages — individual rates vary based on ovarian reserve, health, and partner factors.

Using the geometric formula P = 1 − (1 − monthly rate)^12: age 25 ≈ 97%; age 30 ≈ 93%; age 35 ≈ 85%; age 38 ≈ 72%; age 40 ≈ 72%; age 42 ≈ 52%; age 45 ≈ 21%. These are estimates for the average woman at each age with no known fertility issues. Actual rates vary by individual. Note that 'trying for 12 months' is the threshold for seeking evaluation only for women under 35.

Fertility begins declining gradually in the late 20s, more noticeably in the early 30s, and significantly after age 35. The decline accelerates further after 37–38. At 35, the ACOG notes a 'substantial decrease in fertility' and recommends earlier evaluation (after 6 months). The most dramatic decline occurs between 40 and 45. However, 'decline' describes population averages — individual women vary substantially, and some women in their early 40s have better ovarian reserves than women in their mid-30s.

Miscarriage risk increases with maternal age due to rising chromosomal abnormality rates in eggs: under 30 ≈ 10%; age 30–34 ≈ 12%; age 35–37 ≈ 17%; age 38–40 ≈ 25%; age 41–44 ≈ 35%; age 45+ ≈ 50%. These figures represent clinical pregnancy loss risk (after confirmation by ultrasound). Very early losses (chemical pregnancies) that occur before a missed period are additional. Most miscarriages are caused by chromosomal abnormalities unrelated to maternal health behaviors.

Down syndrome (Trisomy 21) risk per pregnancy increases sharply with maternal age: age 25 ≈ 1 in 1,250; age 30 ≈ 1 in 940; age 35 ≈ 1 in 350; age 38 ≈ 1 in 179; age 40 ≈ 1 in 100; age 42 ≈ 1 in 68; age 45 ≈ 1 in 30. Prenatal screening (NIPT, nuchal translucency ultrasound, quad screen) can detect Down syndrome and other chromosomal conditions early in pregnancy. ACOG recommends offering screening to all pregnant women regardless of age.

ACOG guidelines: under 35 — seek evaluation after 12 months of regular unprotected intercourse without conception; age 35–37 — seek evaluation after 6 months; age 38 or older — seek evaluation after 3 months. Earlier evaluation is appropriate for anyone with known risk factors: irregular periods, prior pelvic infections, endometriosis, prior ectopic pregnancy, recurrent miscarriage, or a partner with known male factor infertility. Earlier referral is never wrong.

Yes. Male fertility declines with age, though less dramatically than female fertility. Sperm count, motility, and morphology decline gradually from the late 30s. More significantly, sperm DNA fragmentation increases with age, which raises miscarriage risk and (less conclusively) risk of certain conditions in offspring. ACOG considers paternal age above 40 a mild risk factor. Male factor infertility (regardless of age) accounts for approximately 40–50% of all infertility cases and should be evaluated early with a semen analysis.

For women: AMH (Anti-Müllerian Hormone) and antral follicle count (AFC) by ultrasound are the best measures of ovarian reserve. FSH and estradiol on day 3 of the cycle are additional markers. These tests assess egg quantity; egg quality is harder to measure directly (age is the best proxy). A hysterosalpingogram (HSG) checks fallopian tube patency. For men: semen analysis covers count, motility, and morphology. Both partners should be evaluated early, as male factor is equally common.

IVF success rate (live birth per transfer) declines sharply with maternal age when using the woman's own eggs: age 35 ≈ 40%; age 38 ≈ 28%; age 40 ≈ 20%; age 42 ≈ 10%; age 44 ≈ 5%. With donor eggs from a young donor, success rates are much higher (50–60%) regardless of the recipient's age, because the determining factor is the egg's age, not the uterus. Preimplantation genetic testing (PGT-A) identifies chromosomally normal embryos for transfer, which improves live birth rates per transfer especially for older women.

Age is the dominant factor, but lifestyle matters too. Smoking significantly accelerates ovarian aging and is associated with earlier menopause. BMI outside the normal range (18.5–25) affects hormonal balance and conception rates. Excessive exercise can suppress ovulation. Alcohol and heavy caffeine consumption are associated with modestly reduced fertility. Stress does not directly prevent conception in most cases but can affect cycle regularity. Prenatal vitamins with folic acid (400–800 mcg) should be started before trying to conceive.

Yes, natural conception after 40 is possible, though monthly rates are lower (approximately 5–10% per cycle at 40, declining further with age). Many women in their early 40s conceive naturally. The key difference from younger ages is that conception takes longer on average, and miscarriage risk is higher when it does occur. ACOG recommends seeking evaluation after 3 months of trying at age 38 or older, rather than waiting 12 months, because of the accelerating age-related decline and the benefit of earlier intervention if needed.