title: Is there an increased risk of twinning after discontinuation of the oral contraceptive pill?
abstract: We investigated whether conception soon after cessation of use of oral contraceptives affects the chance of bearing twins. Unpublished data from a large sample survey of contraceptive practice in Scotland were used to derive oral contraceptive discontinuation rates by month over the decade 1972-82 and these were related to estimated monozygotic and dizygotic twin birth rates and proportions by month in Scotland from 1974-82, using regression techniques. The results provide some support for the hypothesis that there is an increased risk of conceiving monozygotic twins within a year of ceasing to use oral contraceptives.
authors.affiliation: Department of Community Medicine and General Practice, Radcliffe Infirmary, Oxford.
authors.forename: M F
authors.initials: MF
authors.lastname: Murphy
authors.forename: M J
authors.initials: MJ
authors.lastname: Campbell
authors.forename: M
authors.initials: M
authors.lastname: Bone
mesh_terms: D000293:Adolescent; D000328:Adult; D003276:Contraceptives, Oral; D005260:Female; D006801:Humans; D008875:Middle Aged; D011247:Pregnancy; D011272:Pregnancy, Multiple; D012044:Regression Analysis; D012307:Risk Factors; D012606:Scotland; D014427:Twins
chemical_list: D003276:Contraceptives, Oral