EDITOR—In their review of ectopic pregnancy, Tay et al report that previous female sterilisation and current use of an intrauterine contraceptive device are risk factors only when patients with ectopic pregnancy are compared with pregnant controls and not with non-pregnant women.1 However, we published a review on the effects of oral contraceptives after fertilisation, in which we reviewed data indicating that the ratio of extrauterine to intrauterine pregnancies is increased for women taking combined oral contraceptives and progestogen only pills, …