Is there an increased risk of twinning after discontinuation of the oral contraceptive pill?
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 Unpublished data from a large sample survey of contraceptive practice in Scotland were used to derive oral contraceptive discontinuation rates by month over the decade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.
Murphy
M F
MF
Department of Community Medicine and General Practice, Radcliffe Infirmary, Oxford.
Campbell
M J
MJ
Bone
M
M
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
D003276:Contraceptives, Oral