Emergency contraception consists of methods that can be used by women after sexual intercourse to prevent pregnancy. Emergency contraception methods have varying ranges of effectiveness depending on the method and timing of administration. Four options are available in the United States: the Cu-IUD and three types of ECPs.
- UPA in a single dose (30 mg)
- Levonorgestrel in a single dose (1.5 mg) or as a split dose (1 dose of 0.75 mg of levonorgestrel followed by a second dose of 0.75 mg of levonorgestrel 12 hours later)
- Combined estrogen and progestin in 2 doses (Yuzpe regimen: 1 dose of 100 µg of ethinyl estradiol plus 0.50 mg of levonorgestrel followed by a second dose of 100 µg of ethinyl estradiol plus 0.50 mg of levonorgestrel 12 hours later)
- The Cu-IUD can be inserted within 5 days of the first act of unprotected sexual intercourse as an emergency contraceptive.
- In addition, when the day of ovulation can be estimated, the Cu-IUD can be inserted beyond 5 days after sexual intercourse, as long as insertion does not occur >5 days after ovulation.
- ECPs should be taken as soon as possible within 5 days of unprotected sexual intercourse.
Comments and Evidence Summary. Cu-IUDs are highly effective as emergency contraception (283) and can be continued as regular contraception. UPA and levonorgestrel ECPs have similar effectiveness when taken within 3 days after unprotected sexual intercourse; however, UPA has been shown to be more effective than the levonorgestrel formulation 3–5 days after unprotected sexual intercourse (284). The combined estrogen and progestin regimen is less effective than UPA or levonorgestrel and also is associated with more frequent occurrence of side effects (nausea and vomiting) (285). The levonorgestrel formulation might be less effective than UPA among obese women (286).
Two studies of UPA use found consistent decreases in pregnancy rates when administered within 120 hours of unprotected sexual intercourse (284,287). Five studies found that the levonorgestrel and combined regimens decreased risk for pregnancy through the fifth day after unprotected sexual intercourse; however, rates of pregnancy were slightly higher when ECPs were taken after 3 days (288–292). A meta-analysis of levonorgestrel ECPs found that pregnancy rates were low when administered within 4 days after unprotected sexual intercourse but increased at 4–5 days (293) (Level of evidence: I to II-2, good to poor, direct).
- An advance supply of ECPs may be provided so that ECPs will be available when needed and can be taken as soon as possible after unprotected sexual intercourse.
Comments and Evidence Summary. A systematic review identified 17 studies that reported on safety or effectiveness of advance ECPs in adult or adolescent women (294). Any use of ECPs was two to seven times greater among women who received an advance supply of ECPs. However, a summary estimate (relative risk = 0.97; 95% confidence interval = 0.77–1.22) of five randomized controlled trials did not indicate a significant reduction in unintended pregnancies at 12 months with advance provision of ECPs. In the majority of studies among adults or adolescents, patterns of regular contraceptive use, pregnancy rates, and incidence of STDs did not vary between those who received advance ECPs and those who did not. Although available evidence supports the safety of advance provision of ECPs, effectiveness of advance provision of ECPs in reducing pregnancy rates at the population level has not been demonstrated (Level of evidence: I to II-3, good to poor, direct).
- Advise the woman to start or resume hormonal contraception no sooner than 5 days after use of UPA, and provide or prescribe the regular contraceptive method as needed. For methods requiring a visit to a health care provider, such as DMPA, implants, and IUDs, starting the method at the time of UPA use may be considered; the risk that the regular contraceptive method might decrease the effectiveness of UPA must be weighed against the risk of not starting a regular hormonal contraceptive method.
- The woman needs to abstain from sexual intercourse or use barrier contraception for the next 7 days after starting or resuming regular contraception or until her next menses, whichever comes first.
- Any nonhormonal contraceptive method can be started immediately after the use of UPA.
- Advise the woman to have a pregnancy test if she does not have a withdrawal bleed within 3 weeks.
Levonorgestrel and Combined Estrogen and Progestin ECPs
- Any regular contraceptive method can be started immediately after the use of levonorgestrel or combined estrogen and progestin ECPs.
- The woman needs to abstain from sexual intercourse or use barrier contraception for 7 days.
- Advise the woman to have a pregnancy test if she does not have a withdrawal bleed within 3 weeks.
Comments and Evidence Summary.The resumption or initiation of regular hormonal contraception after ECP use involves consideration of the risk for pregnancy if ECPs fail and the risks for unintended pregnancy if contraception initiation is delayed until the subsequent menstrual cycle. A health care provider may provide or prescribe pills, the patch, or the ring for a woman to start no sooner than 5 days after use of UPA. For methods requiring a visit to a health care provider, such as DMPA, implants, and IUDs, starting the method at the time of UPA use may be considered; the risk that the regular contraceptive method might decrease the effectiveness of UPA must be weighed against the risk of not starting a regular hormonal contraceptive method.
Data on when a woman can start regular contraception after ECPs are limited to pharmacodynamic data and expert opinion (295–297). In one pharmacodynamic study of women who were randomly assigned to either UPA or placebo groups mid-cycle followed by a 21-day course of combined hormonal contraception found no difference between UPA and placebo groups in the time for women’s ovaries to reach quiescence by ultrasound and serum estradiol (296); this finding suggests that UPA did not have an effect on the combined hormonal contraception. In another pharmacodynamic study with a crossover design, women were randomly assigned to one of three groups: 1) UPA followed by desogestrel for 20 days started 1 day later; 2) UPA plus placebo; or 3) placebo plus desogestrel for 20 days (295). Among women taking UPA followed by desogestrel, a higher incidence of ovulation in the first 5 days was found compared with UPA alone (45% versus 3%, respectively), suggesting desogestrel might decrease the effectiveness of UPA. No concern exists that administering combined estrogen and progestin or levonorgestrel formulations of ECPs concurrently with systemic hormonal contraception decreases the effectiveness of either emergency or regular contraceptive methods because these formulations do not have antiprogestin properties like UPA. If a woman is planning to initiate contraception after the next menstrual bleeding after ECP use, the cycle in which ECPs are used might be shortened, prolonged, or involve unscheduled bleeding.
Nausea and Vomiting
- Levonorgestrel and UPA ECPs cause less nausea and vomiting than combined estrogen and progestin ECPs.
- Routine use of antiemetics before taking ECPs is not recommended. Pretreatment with antiemetics may be considered depending on availability and clinical judgment.
Vomiting Within 3 Hours of Taking ECPs
- Another dose of ECP should be taken as soon as possible. Use of an antiemetic should be considered.
Comments and Evidence Summary. Many women do not experience nausea or vomiting when taking ECPs, and predicting which women will experience nausea or vomiting is difficult. Although routine use of antiemetics before taking ECPs is not recommended, antiemetics are effective in some women and can be offered when appropriate. Health-care providers who are deciding whether to offer antiemetics to women taking ECPs should consider the following: 1) women taking combined estrogen and progestin ECPs are more likely to experience nausea and vomiting than those who take levonorgestrel or UPA ECPs; 2) evidence indicates that antiemetics reduce the occurrence of nausea and vomiting in women taking combined estrogen and progestin ECPs; and 3) women who take antiemetics might experience other side effects from the antiemetics.
A systematic review examined incidence of nausea and vomiting with different ECP regimens and effectiveness of antinausea drugs in reducing nausea and vomiting with ECP use (298). The levonorgestrel regimen was associated with significantly less nausea than a nonstandard dose of UPA (50 mg) and the standard combined estrogen and progestin regimen (299–301). Use of the split-dose levonorgestrel showed no differences in nausea and vomiting compared with the single-dose levonorgestrel (288,290,292,302) (Level of evidence: I, good-fair, indirect). Two trials of antinausea drugs, meclizine and metoclopramide, taken before combined estrogen and progestin ECPs, reduced the severity of nausea (303,304). Significantly less vomiting occurred with meclizine but not metoclopramide (Level of evidence: I, good-fair, direct). No direct evidence was found regarding the effects of vomiting after taking ECPs.
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Pages in this Report
- Table of Contents
- US SPR 2016
- How To Be Reasonably Certain that a Woman Is Not Pregnant
- Intrauterine Contraception
- Combined Hormonal Contraceptives
- Progestin-Only Pills
- Standard Days Method
- ›Emergency Contraception
- Female Sterilization
- Male Sterilization
- When Women Can Stop Using Contraceptives
- Summary Chart of U.S. Medical Eligibility Criteria for Contraceptive Use, 2016
- When To Start Using Specific Contraceptive Methods
- Examinations and Tests Needed Before Initiation of Contraceptive Methods
- Routine Follow-Up After Contraceptive Initiation
- Management of Women with Bleeding Irregularities While Using Contraception
- Management of Intrauterine Devices When Users are Found To Have Pelvic Inflammatory Disease