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Q Does advance provision of emergency contraception (EC) to women reduce pregnancy rates without increasing rates of sexually transmitted diseases (STDs) or reducing use of more effective methods of contraception?
Cochrane Central Register of Controlled Trials, Medline, EMBASE/Excerpta Medica, POPLINE, and International Consortium for Emergency Contraception website (to August 2006); reference lists; and experts.
Study selection and assessment:
English-language randomised controlled trials (RCTs) that compared provision of EC in advance of need with a control intervention (counselling, which may or may not have included a discussion of EC; information about EC; or provision of EC on request by a clinic or pharmacy) in women of reproductive age. 8 RCTs (n = 6389) met the selection criteria. Quality of individual trials was assessed based on randomisation method, allocation concealment, sample size calculation, and loss to follow-up.
pregnancy, STD infection, use of EC, timing of EC use, unprotected intercourse, and use of condoms.
Groups did not differ for pregnancy, STD infection, (table) unprotected intercourse (6 RCTs), or use of condoms (6 RCTs). More women who received advance EC used EC at least once or multiple times during the study (table). The time interval between unprotected intercourse and use of EC was shorter in the advance EC group than in the control group in 3 RCTs (11–14 h v 22–36 h) but the same in 1 RCT (8 h).
Although advance provision of emergency contraception to women of reproductive age increases use of emergency contraception and shortens the time interval between unprotected intercourse and use of emergency contraception, based on current studies, it does not reduce the risk of unplanned pregnancy more than standard provision of emergency contraception. Advance provision does not increase the risk of sexually transmitted disease or reduce the use of more effective methods of contraception.
The review by Polis et al confirms that advance provision of EC does not increase rates of STD infection, decrease condom use, or encourage adoption of less reliable contraceptive methods. However, the review also found that advance EC does not reduce unintended pregnancy at a population level. Although pregnancy rates differ across age groups within the “reproductive age” category, there is no reason to expect that, within each trial, the groups would have differed in their proportions of younger women at higher risk.
Some of the studies used the progestagen-only EC, levonorgestrel, the mode of action of which is not clearly understood, although it is thought to involve inhibition of ovulation.1 Limited data exist on how levonorgestrel works if taken after ovulation.1 Additionally, there are very few days in the menstrual cycle when there is no risk of pregnancy after unprotected sexual intercourse. Predicting these days is notoriously difficult; one prospective study showed that only 30% of 221 women had their fertile period within the expected days of the menstrual cycle.2 The review by Polis et al did not provide information on the time in the cycle the episodes of unprotected intercourse that led to pregnancy occurred, but again this would have been distributed similarly in both groups of the trials.
The earlier EC is taken after unprotected intercourse, the more effective it is. The review found shorter average times to use with advance EC, but still this advantage did not reduce pregnancy rates.
Finally, >70% of women in the advance EC group who became pregnant did not use EC in the cycle in which they conceived. It is likely that this high incidence of non-use of EC in conception cycles is the main reason for the observed lack of pregnancy prevention.
For clinicians, the review by Polis et al provides reassuring information about the lack of harm in relation to condom use and incidence of STDs. Providers of EC need to consider the behavioural issues surrounding the failure to use EC when needed, even when it is readily available.
For correspondence: MsC Polis, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
Source of funding: no external funding.
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