RHL Commentary by Suneeta Mittal
EVIDENCE SUMMARY
This review analyzed data form 48 trials including 33110 women using different methods of emergency contraception in varying doses including high dose estrogens, the Yuzpe regimen (estrogen +progestogen), progestogen alone (levonorgestrel), danazol, mifepristone in varying doses, and mifepristone with anordrin, misoprostol or tamoxifen and intra-uterine device. Most (37/48) of these trials are from China.
Comparative evaluation of different interventions found that any form of emergency contraception is better than no intervention or placebo. levonorgestrel and mifepristone had higher efficacy and fewer side effects than the Yuzpe regimen and danazol; independent of time elapsed since intercourse. Single dose (1.5mg) of levonorgestrel is as effective as standard two doses(0.75mg) at 12 hours interval, with no difference in side effects except headache, which is slightly more in women taking single dose. Efficacy and side effects with mifepristone in high dose (>50mg), mid dose (25-50mg) and low dose (<25mg) is similar to levonorgestrel and better than Yuzpe regimen, except the menstrual delay which was more pronounced with high and mid dose of mifepristone. The Yuzpe regimen, danazol and levonorgestrel had no significant effect on the menstrual cycle. Mifepristone alone was more effective than anordrin. Combining mifepristone with anordrin or tamoxifen or misoprostol did not have any significant effect on the pregnancy rate, but delay in menses was more common after using a combination with anordrin. Single dose Yuzpe (half dose given once), did not decrease the efficacy, but the side effect profile improved significantly.
Five cases of ectopic pregnancy were reported, 3 following mifepristone use and 2 after levonorgestrel as two doses 12 hours apart. Eight healthy infants have been delivered with no adverse effects following use of different emergency contraceptives.
The review examined randomized controlled and controlled clinical trials comparing different methods of emergency contraception or any method with nothing or placebo, reporting on clinical outcomes, namely efficacy (number of pregnancies) and side-effects, ectopic pregnancy and delay in menses. Comparative studies without random allocation of subjects have been excluded.
The trials have been identified and retrieved by electronic searches of Cochrane Controlled Trials Register, MEDLINE and EMBASE; from WHO resources and from pharmaceutical companies. All trials have been scored qualitatively (1), and treatment results have been calculated using relative risk estimates. The observed number of pregnancies in comparison to expected number of pregnancies calculated by estimated probability of conception on the day of intercourse in relation to menstrual cycle has been used to evaluate the efficacy of emergency contraception regimen. Besides comparison of different regimens, other factors affecting the success of emergency contraception viz. coitus-treatment interval and risk status of women were also evaluated. The review is unbiased and thorough. The data is clearly tabulated and graphically depicted for different methods taking in consideration all the parameters evaluated.
The full RHL commentary also includes sections on: Relevance
- Magnitude of the problem
- Applicability of the results
- Implementation of the intervention
Research
References
This document should be cited as: Suneeta Mittal. Interventions for emergency contraception: RHL commentary (last revised: 23 September 2004). The WHO Reproductive Health Library, No 9, Update Software Ltd, Oxford, 2006. www.rhlibrary.com
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