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Primary care emergencies - Emergency contraception

GPs Dr Chantal Simon, Dr Karen O’Reilly, Dr Robin Proctor and Dr John Buckmaster give a simple guide to prescribing

GPs Dr Chantal Simon, Dr Karen O'Reilly, Dr Robin Proctor and Dr John Buckmaster give a simple guide to prescribing


Ask the woman patient:

• When her last menstrual period started and usual cycle length

• When she had unprotected intercourse and whether there were other episodes of unprotected intercourse during this cycle

• What other medication she is taking, including contraceptive pills

• Whether she has any chronic or current medical conditions.

Hormonal emergency contraception

Use levonorgestrel 1.5mg – available OTC and on prescription. Single dose taken <72 hours (three days) after unprotected intercourse. The sooner it is taken, the greater the efficacy:

0-24 hours – 95% efficacy

25-48 hours – 85% efficacy

49-72 hours – 58% efficacy.

Levonorgestrel is effective up to 120 hours post-intercourse, but effectiveness decreases the longer the delay.


Acute active porphyria, severe liver disease, allergy.

Possible pitfalls

• Vomiting <three hours after taking levonorgestrel – give a replacement dose. If an anti-emetic is required, prescribe domperidone.

• Enzyme-inducing drugs, such as anti-epileptics, St John's wort – efficacy may be decreased. Consider a copper-IUD or increase dose of levonorgestrel to 3mg (1500µg immediately and 1500µg 12 hours later – unlicensed).

Copper-containing IUD

Insertion of an IUD is more effective than hormonal emergency contraception and prevents nearly 100% of pregnancies:

• Copper IUDs (not Mirena) can be inserted for emergency contraception within 120 hours (five days) after unprotected intercourse

• Test for sexually transmitted diseases with endocervical swabs if at risk, cover insertion with antibiotics, for example azithromycin 1g stat

• If intercourse has occurred more than five days previously, an IUD can still be inserted up to five days after the earliest likely calculated ovulation – for example, within the minimum period before implantation

• There is a small increase in pelvic infections in the 20 days following insertion of an IUD.


This should take place three to four weeks after prescribing emergency contraception or inserting an IUD – sooner, if heavy vaginal bleeding or pelvic pain. Include:

• Checking the patient is not pregnant – may need a pregnancy test

• Talking about regular methods of contraception that would prevent pregnancy and the need for emergency contraception in future

• Screening for sexually transmitted diseases, if needed

• If the patient is pregnant, discussing options for pregnancy.

This article is an extract from Emergencies in Primary Care published by Oxford University Press, edited by Dr Chantal Simon, Dr Karen O'Reilly, Dr Robin Proctor and Dr John Buckmaster: ISBN: 978-0-19-857068-4

Emergency contraception

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