Studies of any design that provided primary data on the effects of interventions with different levels of access to emergency contraceptive pills were eligible for inclusion in the review.
The participants, where reported, included condom users, spermicide users, postpartum women, adolescents, family planning clients, emergency contraception and abortion clients, and new acceptors of oral contraceptive pills or condoms. The studies were conducted in India, USA, China, Scotland, Zambia and Ghana.
The interventions varied in terms of their aggressiveness (e.g. number of packages of emergency contraceptive pills initially provided, replacement versus non-replacement of lost and used pills) and the emergency contraceptive pill regimen used (i.e. Yuzpe, levonorgestrel or mifepristone regimens). The interventions reported in uncontrolled observational studies included legislation allowing distribution of emergency contraceptive pills (over the counter or from a pharmacist), provision of an advance supply of emergency contraceptive pills, implementation of a telephone prescription service, and the introduction of a dedicated product by a pharmaceutical company.
All included studies evaluated emergency contraception pill use, though not all reported pregnancies. Pregnancies were typically assessed by participant report, in some cases supplemented by chart review and scheduled or indicated pregnancy testing. Emergency contraceptive pill use data were typically obtained through participant report.
Study designs included randomised controlled trials (RCTs), prospective cohort studies and uncontrolled observational studies.
Two reviewers independently selected studies for inclusion in the review.