title: Maternal age, dizygotic twinning rates and age at menopause.
abstract: The dizygotic (DZ) twinning rate declines after about maternal age 38 in Caucasian populations. Bulmer (1970) offered the explanation that waning ovarian function causes a decline in rates of double ovulation in originally twin-prone women. The present note suggests that some small part of the decline is caused by the earlier cessation of ovulation altogether in these women (presumably also as a result of waning ovarian function).
mesh_terms: D000328:Adult; D000367:Age Factors; D005260:Female; D006801:Humans; D008423:Maternal Age; D008593:Menopause; D008875:Middle Aged; D010060:Ovulation; D011247:Pregnancy; D011272:Pregnancy, Multiple; D014429:Twins, Dizygotic; D044465:White People