Article Text
Abstract
Introduction Unprotected intercourse after oral emergency contraception (EC) significantly increases pregnancy risk. This underlies the importance of promptly starting effective, ongoing contraception – known as ‘quick starting.’ However, theoretical concern exists that quick starting might interact with EC or hormonal contraception (HC) potentially causing adverse side effects.
Methods A systematic review was conducted, evaluating quick starting HC after oral EC (levonorgestrel 1.5mg [LNG] or ulipristal acetate 30mg [UPA]). PubMed, EMBASE, The Cochrane Library, ICTRP, ClinicalTrials.gov and relevant reference lists were searched in February 2016. A lack of comparable studies prevented meta-analysis.
Results Three randomised controlled trials were identified. Two biomedical studies suggested HC action was unaffected by quick starting after UPA; one study examined ovarian quiescence (OR: 1.27; 95% CI 0.51 to 3.18) while taking combined oral contraception (COC). Another assessed cervical mucus impenetrability (OR: 0.76; 95% CI 0.27 to 2.13) while taking progestogen-only pills (POP). Quick starting POP reduced the ability of UPA to delay ovulation (OR: 0.04; 95% CI 0.01 to 0.37). Side effects (OR: 1.22; 95% CI 0.48 to 3.12) and unscheduled bleeding (OR: 0.53; 95% CI 0.16 to 1.81) were unaffected by quick starting COC after UPA. Another study reported higher self-reported contraceptive use at eight weeks among women quick starting POP after LNG, compared with women given LNG alone (OR: 6.73; 95% CI 2.14 to 21.20).
Discussion Limited evidence suggests quick starting HC after UPA does not reduce HC efficacy, however it reduces UPA efficacy. Consequently, women should delay starting HC after UPA.