Number of oocytes in female

Range at ∼20 weeks gestation several million: at birth ∼1–2 million: at age 37.5 ∼25,000: at age 51 1,000 oocytes
Organism Human Homo sapiens
Reference Lobo RA. Early ovarian ageing: a hypothesis. What is early ovarian ageing? Hum Reprod. 2003 Sep18(9):1762-4. p.1762 left column bottom paragraphPubMed ID12923124
Primary Source Faddy, M.J., Gosden, R.G., Gougeon, A., Richardson, S.J. and Nelson, J.F. (1992) Accelerated disappearance of ovarian follicles in mid-life: Implications for forecasting menopause. Hum. Reprod., 7, 1342–1346 AND Gougeon, A., Ecochard, R. and Thalabard, J.C. (1994) Age-related changes of the population of human ovarian follicles: Increase in the disappearance rate of non-growing and early-growing follicles in aging women. Biol. Reprod., 50, 653–663.PubMed ID1291557, 8167237
Comments "The greatest number of oocytes (several million [~7E6 according to wikipedia link ]) are present at ~20 weeks gestation. At birth, this number is ~1–2×10^6, and then the rate of atresia/apoptosis is relatively constant until age 37.5 years when there are ~25,000 oocytes. From this point, atresia accelerates until the average age of menopause (51 years) when only 1,000 oocytes remain. (primary sources) The accelerated rate of atresia at age 37–38 is often associated with increases in FSH [Follicle-stimulating hormone], decreased fecundity (Scott et al., 1989 Wood et al., 1992) and an increased rate of aneuploidy."
Entered by Uri M
ID 111451