Yuzpe Regimen for Emergency Contraception

The Yuzpe regimen uses ordinary combined oral contraceptive tablets in two doses 12 hours apart, to give ethinylestradiol and levonorgestrel at emergency contraceptive strength. It prevents about 75% of expected pregnancies and is the least effective oral option. It is used only when levonorgestrel, ulipristal acetate and the copper IUD cannot be obtained.

Mechanism. Delay or prevention of ovulation, with possible slowing of ovum transport. It does not end an established pregnancy.

Formulations. Only monophasic pills containing levonorgestrel with ethinylestradiol are used. Biphasic and triphasic pills, and pills containing other progestins, are not interchangeable.

Effectiveness. About 8 pregnancies in 100 women follow one act of unprotected intercourse in the fertile phase. After oral emergency contraception, 1 to 2 in 100 become pregnant, and the Yuzpe regimen sits at the weaker end of that range.

Duration and return to fertility. Protection covers the episode treated. Fertility returns at once.

Eligibility. Category 1 for breastfeeding, previous ectopic pregnancy, sexual assault, obesity and enzyme inducers. Category 2 for previous ischaemic heart disease, stroke or other thromboembolic disease, angina, migraine and severe liver disease including jaundice. Because the regimen contains oestrogen, choose levonorgestrel, ulipristal acetate or the copper IUD in category 2 patients whenever one is available, and give the Yuzpe regimen without delay only if none can be obtained.

Not indicated. Known pregnancy. Accidental use causes no known harm.

Interactions. Enzyme inducers lower hormone levels and the effect.

Counselling points for the clinician. State that nausea and vomiting are more common than with other options and that effectiveness is lower. Obtain consent, protect confidentiality and exclude coercion. Offer condoms for dual protection.

Special groups.

• Breastfeeding: choose levonorgestrel first. Short oestrogen exposure is acceptable when nothing else exists.

• Postpartum: not needed before 4 weeks after birth.

• Adolescents: no age limit applies.

Regimen.

• Drug: monophasic combined pills, by mouth.

• With 50 microgram ethinylestradiol and 250 micrograms levonorgestrel in each tablet: 2 tablets as the first dose and 2 tablets 12 hours later.

• With 30 microgram ethinylestradiol and 150 micrograms levonorgestrel in each tablet: 4 tablets as the first dose and 4 tablets 12 hours later (8 tablets in all).

• Timing: first dose as soon as possible, within 120 hours. Frequency: two doses 12 hours apart. Confirm the strength on the pack before counting tablets.

• Duration of protection: the episode treated only. Backup: condoms until the next method takes effect.

Antiemetic. Ondansetron 4 mg by mouth 30 to 60 minutes before the first dose when nausea is likely, repeated once after 8 hours if needed. Maximum 12 mg in 24 hours, for no more than 2 days. Limit to 8 mg in 24 hours in severe liver disease. No kidney adjustment is needed. Avoid in congenital long QT syndrome. In pregnancy use only when the benefit is clear. Short courses are acceptable in breastfeeding.

Vomiting. Within 2 hours of a dose, repeat that dose with an antiemetic. If vomiting continues, place the repeat tablets high in the vagina. After more than 2 hours, give nothing further.

Pregnancy exclusion. Pregnancy is reasonably excluded when there has been no unprotected intercourse since the last normal menses and menses are not overdue. A test is not required before one recent episode. If menses are more than 7 days late, test.

Starting ongoing contraception. Combined and progestin-only pills start the day after the second dose, with 7 days of backup for combined pills and 2 days for progestin-only pills. An injectable may be given the same day with 7 days of backup. A copper IUD may be placed the same day. An implant starts within the first 7 days of the next menses, with condoms or pills until then.

Follow up. Advise return if menses are more than 7 days late or if lower abdominal pain or unusual bleeding occurs. Test 3 weeks after the episode if menses have not started.

Expected effects. Nausea is common, with vomiting, breast tenderness, headache, fluid retention and irregular bleeding.

Management.

• Mild nausea: reassure and advise food or milk.

• Severe nausea or vomiting: ondansetron 4 mg by mouth as one dose, repeated once after 8 hours if needed, maximum 12 mg in 24 hours for no more than 2 days (8 mg in 24 hours in severe liver disease). The repeat-dose rule for vomiting within 2 hours applies to each dose.

• Headache with fluid retention: a mild analgesic if blood pressure is normal. Refer if blood pressure is high.

• Irregular bleeding: reassure if not pregnant and arrange a reliable method.

Venous thromboembolism. Risk from one short course is very small. Advise return for calf pain or swelling, chest pain or breathlessness.

Failure and pregnancy. A pregnancy after the regimen is not harmed by it. Assess for ectopic pregnancy when a positive test comes with pain or bleeding.

Repeated use. The regimen is poorly suited to repeated use. Offer a regular method.

Referral and escalation. Refer for severe abdominal pain, fainting, signs of venous thromboembolism or a positive pregnancy test with pain or bleeding.