title: Multiple pregnancy and fetal abnormalities in association with oral contraceptive usage.
abstract: 1,000 multiple births were examined in relation to maternal exposure to an oral contraceptive before conception. There was a significantly higher rate of monozygotic twinning among pregnancies which took place within 6 months of cessation of the contraceptive. In the monozygotic group there was a significant increase in the incidence of congenital abnormalities (P less than 0.01) when conception occurred within 3 months of cessation of the contraceptive.
mesh_terms: D000014:Abnormalities, Drug-Induced / Q000453:epidemiology* / Q000209:etiology; D001315:Australia; D003276:Contraceptives, Oral / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011272:Pregnancy, Multiple; D012189:Retrospective Studies; D014427:Twins; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic
chemical_list: D003276:Contraceptives, Oral