Emergency Contraception FAQs « Below the Belt: Women's Health

Emergency Contraception Part Three

In this blog series, we’ve been discussing emergency contraception pills (ECP) and covered the recently approved ECP called Ella. It can be used for emergency prevention of pregnancy for up to five days after unprotected sex. In this post, I want to answer your frequently asked questions about ECPs.

How late is too late to take an ECP?
For the non-prescription types (e.g., Plan B) the FDA has approved use for up to 72 hours after unprotected sex. While not as effective when started after 72 hours, there are studies which show Plan B regimens can still decrease risk of pregnancy when taken up to 120 hours after unprotected sex (Glasier, 2010, von Hertzen, 2002).

Studies have also suggested that using the Yuzpe method up to 120 hours after unprotected sex may also be effective (Ellertson, 2003). Rodriguez and colleagues (2001) gave the Yuzpe regimen to 300 women. The pregnancy rate was 0.8 percent in the less than 72-hour group and 1.8 percent for the 72-to-120-hour group. While sooner is better, up to five days later is still more protective than not using ECPs.

The single dose ella tablet, containing 30 mg of ulipristal acetate, confers excellent protection when used up to five days after intercourse. Ella’s effectiveness did not decrease when immediate use, 48-72 hours, was compared 96-120 hours (Fine, 2010).

When will I get my period?
Generally, we tell women that their period can arrive anywhere between a week before or a week after the expected date of flow. For women utilizing the Yuzpe, 98 percent will have a menstrual period within 21 days of taking the ECPs (Hatcher, 1998). In a study of over 4,000 women using a Plan B type regimen (vonHertzen, 2002), the majority of women had their periods within 48 hours of the expected date.

With Ella use, menstruation arrived about 3 days later than expected, but the number of days of flow was unchanged (Fine, 2010).

Given that ECPs work by impacting ovulation, the time in one’s cycle when ECPs are used might influence when menstruation is likely to return. Two small studies have shown that when a Plan B type is used about three days before ovulation, onset of flow may be delayed. When taken closer to ovulation, or later, periods came earlier or near their expected time (Okewole, 2007 & Hapangama, 2001).

I didn’t get my period. When should a home pregnancy test be done?
A sensitive home pregnancy test should be accurate about 14 days after unprotected sex. If the test is negative, and your period does not arrive, test again a week later.

In conclusion, ECPs only work if they are used. A group of 2,100 women in California were enrolled in a six-month study. Those who were given ECPs to take home were twice as likely to use ECPs when needed, when compared with those just given information or access for emergency contraception. Yet, within the six months of follow up, about half of the women who had unprotected sex still did not use any emergency contraception (Raine, 2005). Even with the introduction of a new “morning after pill,” women still have to decide to use it.

If you have any more questions about emergency contraception I would urge you to check this excellent website from Princeton University that answers more FAQs about emergency contraception.

Read more from the series: