The introduction of a new oral emergency contraceptive (EC), ulipristal acetate (UPA) with a higher up-front cost, has led many clinicians to consider trying to identify women at higher risk of pregnancy so that they can be preferentially offered the drug that works closer to ovulation. These attempts, however well meaning, are flawed, are not based on the published evidence, go against best practice guidance as established by the Clinical Effectiveness Unit (CEU), and may deprive women at definite risk of pregnancy from making an informed choice.

If it were possible to determine, consistently and reasonably accurately, where a woman is in relation to ovulation we could reassure the majority of women that they did not need any EC. We know levonorgestrel …