From the Guidelines
Emergency contraception options include levonorgestrel (Plan B One-Step, 1.5 mg taken as a single dose within 72 hours of unprotected sex), ulipristal acetate (ella, 30 mg single dose effective up to 120 hours after unprotected sex), and the copper IUD (ParaGard, which can be inserted up to 5 days after unprotected sex and provides ongoing contraception). These options are effective in preventing pregnancy when used as directed, with the copper IUD being the most effective method, having a failure rate of less than 1% 1. The hormonal methods, including levonorgestrel and ulipristal acetate, work primarily by delaying or preventing ovulation, not by disrupting an established pregnancy, and are available over-the-counter or by prescription, respectively 1.
The choice of emergency contraception method depends on various factors, including the time elapsed since unprotected sex, the patient's weight, and the availability of the method. Ulipristal acetate may be more effective than levonorgestrel formulations after the first 72 hours and for women who are overweight or obese 1. The copper IUD can be inserted within 5 days of the first act of unprotected sexual intercourse as an emergency contraceptive and provides ongoing contraception 1.
It is essential to note that emergency contraception is most effective when taken as soon as possible after unprotected sex. Side effects are generally mild and may include nausea, headache, fatigue, and changes in menstrual bleeding. If vomiting occurs within 2-3 hours of taking hormonal emergency contraception, the dose should be repeated. Emergency contraception should not be used as a regular birth control method as it is less effective than consistent use of other contraceptive methods.
Some key points to consider when prescribing emergency contraception include:
- The patient's medical history and any potential contraindications to the method
- The patient's weight and potential impact on the effectiveness of the method
- The availability of the method and any potential barriers to access
- The importance of using emergency contraception as soon as possible after unprotected sex
- The need for follow-up care and potential provision of ongoing contraception.
From the FDA Drug Label
Levonorgestrel tablet is emergency contraception that helps prevent pregnancy after birth control failure or unprotected sex. Levonorgestrel tablet is a backup or emergency method of birth control you can use when: your regular birth control was used incorrectly or failed you did not use any birth control method
14 CLINICAL STUDIES Two multicenter clinical studies evaluated the efficacy and safety of ella.
An open-label study provided the primary data to support the efficacy and safety of ulipristal acetate for emergency contraception when taken 48 to 120 hours after unprotected intercourse A single-blind comparative study provided the primary data to support the efficacy and safety of ulipristal acetate for emergency contraception when taken 0 to 72 hours after unprotected intercourse
Medications used for emergency contraception include:
These medications are used as a backup method to prevent pregnancy after birth control failure or unprotected sex. They should be taken as soon as possible, with levonorgestrel effective up to 72 hours after unprotected sex and ulipristal acetate effective up to 120 hours after unprotected sex.
From the Research
Medications for Emergency Contraception
The following medications are used for emergency contraception:
- Levonorgestrel (LNG) 4, 5, 6, 7, 8
- Ulipristal acetate (UPA) 4, 5, 6
- Copper intrauterine device (IUD) 4, 5, 6
Dosage and Administration
- Levonorgestrel: 1.5 mg single dose or two 0.75 mg doses taken 12 hours apart 7, 8
- Ulipristal acetate: available by prescription, dosage not specified in the studies 5, 6
- Copper IUD: requires a timely visit with a trained clinician for insertion 4, 5, 6
Efficacy and Safety
- Levonorgestrel: prevents around 50-80% of expected pregnancies 4, 7
- Ulipristal acetate: prevents almost two thirds of pregnancies, more effective than levonorgestrel 4, 5, 6
- Copper IUD: prevents over 95% of pregnancies, most effective method of emergency contraception 4, 5, 6
- All methods are extremely safe, with minimal side effects 4, 5, 6