Oral emergency contraception

For a comparison of oral emergency contraception, see Comparison of oral emergency contraception.

The exact effectiveness of oral emergency contraception is unknown; it is estimated to prevent 85% of pregnancies that would otherwise have occurred. Ulipristal is more effective than levonorgestrel for emergency contraception because it can prevent ovulation even when the luteinising hormone (LH) surge has started, but it may be harder to access and more costly.

Table 1. Comparison of oral emergency contraception
Characteristic	Levonorgestrel	Ulipristal
Effectiveness	not as effective as ulipristal or copper IUD	most effective oral EC method; can prevent ovulation just before it occurs not as effective as copper IUD
Use in obesity	effectiveness may be reduced if BMI more than 26 kg/m² or weight more than 70 kg consider a copper IUD or a double dose [NB1]	effectiveness may be reduced if BMI more than 30 kg/m² or weight more than 85 kg consider a copper IUD (double dose of ulipristal not recommended)
Timeframe after unprotected intercourse	up to 96 hours (4 days) [NB2]	up to 120 hours (5 days)
Contraindications	no UKMEC 3 or 4 contraindications	no UKMEC 3 or 4 contraindications
Drug interactions	interacts with drugs that induce liver enzymes; advise double dose [NB1]	interacts with drugs that induce liver enzymes; alternative method recommended (double dose not advised) not recommended if taking oral corticosteroids may be less effective if hormonal contraception used in the previous 7 days or the following 5 days
Use in breastfeeding	can be used safely; no need to interrupt breastfeeding	risk to infant is low; no need to interrupt breastfeeding. To avoid the highest infant exposure, breast milk can be expressed and discarded for 24 hours after taking ulipristal
Options for ongoing contraception	restart or initiate a hormonal method of contraception immediately using Quick Start	must wait 5 days before restarting or initiating a hormonal method of contraception [NB3]
Note: EC = emergency contraception; IUD = intrauterine contraceptive device; TGA = Therapeutic Goods Administration; UKMEC = United Kingdom Medical Eligibility Criteria NB1: Use of a double dose of levonorgestrel is not approved by the Australian TGA. NB2: Use of levonorgestrel beyond 72 hours (3 days) is not approved by the Australian TGA. NB3: Except for levonorgestrel-releasing IUDs, contraceptives containing progestogen may reduce the efficacy of ulipristal if taken within 5 days after taking ulipristal.

For oral emergency contraception, use:

1 levonorgestrel 1.5 mg orally, as a single dose taken as soon as possible and within 96 hours (4 days) of unprotected sexual intercourse contraception, emergency

1 ulipristal 30 mg orally, as a single dose taken as soon as possible and within 120 hours (5 days) of unprotected sexual intercourse. contraception, emergency

Although levonorgestrel is only approved by the Australian Therapeutic Goods Administration (TGA) for use within 72 hours (3 days) of unprotected sexual intercourse, it is effective if taken within 96 hours. Efficacy beyond 96 hours is uncertain.

Levonorgestrel and ulipristal can cause nausea and vomiting; the dose should be repeated with an antiemetic if vomiting occurs within 3 hours of the dose.

A follow-up pregnancy test is recommended:

if the next menstrual period is more than 7 days late (occurs in 18.5% of users) or is lighter than usual
3 weeks after the last episode of unprotected sex if levonorgestrel or ulipristal has been used more than once in a menstrual cycle
4 weeks after starting Quick Start hormonal contraception or 3 weeks after starting the method if no further episodes of unprotected sex occurred in the first week of use.