Elsevier

Obstetrics & Gynecology

Volume 101, Issue 6, June 2003, Pages 1168-1171
Obstetrics & Gynecology

Original research
Extending the time limit for starting the Yuzpe regimen of emergency contraception to 120 hours

https://doi.org/10.1016/S0029-7844(03)00352-1Get rights and content

Abstract

Objective

Current protocols state that the Yuzpe regimen of emergency contraception can be initiated up to 72 hours after unprotected intercourse. The purpose of this study was to determine whether the window for emergency hormonal contraception can be extended to 120 hours.

Methods

In an observational study, we tracked 111 women who requested emergency contraception between 72 and 120 hours after unprotected sex but refused postcoital copper intrauterine devices (IUDs), preferring instead the Yuzpe regimen. We compared failure rates for this group with rates among 675 otherwise similar women who started the same therapy within 72 hours.

Results

Both perfect use (1.9%) and typical use (3.6%) failure rates were low among women presenting between 72 and 120 hours after unprotected intercourse. These rates did not statistically differ from failure rates for the standard Yuzpe regimen (2.0% during perfect use and 2.5% during typical use). Our small sample size of 111, however, gave us just 25% power to detect a doubling in the failure rates (2% to 4%) and 59% power to detect a tripling in the failure rates (2% to 6%).

Conclusion

The 72-hour cutoff for the Yuzpe regimen of emergency contraception appears needlessly restrictive. Women who request this therapy more than 72 hours after unprotected sex should be allowed to receive it, particularly if they decline postcoital insertion of a copper IUD and would otherwise have no options for reducing pregnancy risk.

Section snippets

Materials and methods

In parallel to a double-masked randomized controlled trial of two modifications to the Yuzpe regimen of emergency contraception,8 we conducted a prospective, observational study to evaluate the effectiveness of the Yuzpe regimen when started between 72 and 120 hours after unprotected intercourse (ie, on days 4 or 5) among women refusing copper IUD insertion. We compared failure rates observed in this cohort to rates among otherwise similar women assigned to the control group of the companion

Results

Women enrolled in the observational days 4–5 cohort were similar to those in the standard Yuzpe control arm from the randomized study (Table 1). In both groups, the mean adjusted cycle day of unprotected sex was approximately the same (adjusted cycle day 13). Women in both groups were in their early 20s (mean age 22 years in the days 4–5 group and 24 years in the standard Yuzpe control group). Body mass index was similar (mean 24 in the days 4–5 group and 23 in the standard Yuzpe group). Three

Discussion

Our study suggests that the 72-hour cutoff after unprotected intercourse for starting the Yuzpe regimen of emergency contraception is unnecessarily restrictive. This result is consistent with the finding from a recent, similar Canadian study,9 as well as with a study of levonorgestrel recently published by the World Health Organization.6 Women who present seeking emergency contraception later than the 72-hour cutoff should be counseled that insertion of a copper IUD is the most effective way to

Cited by (0)

The authors represent a larger study team that includes Katrina Abuabara, Alison Bigrigg, Kelly Blanchard, Sarah Carlson, Joanne Gallagher, Anna Glasier, Sue Haskell, Bridget Hinchcliffe, Chris Hesketh, Janice Hunt, Helen King, Becca Loftus-Granberg, Chris McCaig, Tara Shochet, Abigail Norris Turner, Annik Sorhaindo, Alex Stirling, Anne Tyrer, Kate Weaver, and Anne Webb.

The trial was supported by grants from the William and Flora Hewlett Foundation, David & Lucile Packard Foundation, Open Society Institute, Mary Wohlford, John Snyder, the Population Council, an anonymous donor, and Irving and Roberta Schneiderman. Funders did not participate in implementing any stage of the study.

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