Emergency Contraception (EC) is a method of contraception that reduces the risk of conception of an unintended pregnancy following unprotected sexual intercourse (UPSI).

What types of EC are available?

The Copper Intrauterine Device (Cu IUD)

  • The Cu IUD is the most effective method of EC and should be considered by ALL women who have had UPSI and do not want to conceive.
  • The Cu IUD can be inserted for EC within 5 days after the first UPSI in a cycle. Or within 5 days of the earliest estimated date of ovulation, whichever is later.
  • It is the only method of EC that is effective after ovulation has taken place.
  • It also has the advantage of providing immediately effective ongoing contraception.

Ullapristal Acetate (UPA) 

  • The current brand in the UK is called ‘EllaOne’.  UPA acts by delaying ovulation for at least 5 days, until sperm from the episode of unprotected sex for which EC was taken are no longer viable.
  • UPA Can be taken up to 120 hours after UPSI.
  • UPA is not effective as EC when administered after ovulation has taken place.  The Cu IUD should be offered if indicated and acceptable.

Levonogestrel (LNG) 

  • There are a few brands in the UK including Levonelle. UPA acts by delaying ovulation for at least 5 days, until sperm from the episode of unprotected sex for which EC was taken are no longer viable. 
  • LNG Can be taken up to 72 hours after UPSI. The evidence suggests that LNG-EC is ineffective if taken more than 96 hours after UPSI. 
  • LNG is not effective as EC when administered after ovulation has taken place.  UPA can delay ovulation for longer than LNG.   The Cu IUD should be offered if indicated and acceptable.

WHAT YOU MAY NOT KNOW!

Emergency contraception and Weight/Body Mass Index

Evidence suggests that the effectiveness of the Cu IUD is not affected by body weight or Body Mass Index (BMI).  The Cu IUD acts locally at the level of the uterus and so your weight would not be expected to affect its contraceptive effectiveness.

Levonelle appears to be less effective in those with a BMI greater than 26 kg/m2 or weight greater than 70.  If a Cu-IUD is not indicated or not acceptable, such women can be offered EllaOne. If UPA-EC is not suitable, a double-dose (3 mg) of LNG-EC can be used.

EllaOne may be less effective in those with a BMI of greater than 30 or weight greater than 85kg.  Doubling the dose of EllaOne in this case is not recommended.  A Cu IUD should be offered if indicated and acceptable.

What if I take other medication?

The effectiveness of UPA and LNG can be reduced by certain drugs.  These include drugs used in the treatment of epilepsy and tuberculosis, some antifungal medications, over-the-counter St John’s Wort, stomach acid suppressants such as esomeprazole, and some anti-retroviral medication.

It is important that you speak to your local Pharmacist or Doctor if you take any prescribed or over-the-counter medication.

Emergency Contraception and sickness

If you vomit within 2 hours of taking your EC, a second dose will need to be given.  

There are other conditions that can potentially affect the absorption of the EC such as bowel and digestive problems.  It is important that you speak to your local Pharmacist or Doctor if you have a medical condition and require EC.

Pregnancy and Breastfeeding

There is a small risk of expulsion of the Cu IUD at the time of insertion in the period just after delivery.  There is also a small risk of perforating the uterus. Fortunately, these risks are low, however, this risks increase if you are also breastfeeding.

For these reasons, insertion of a Cu IUD should be avoided between 48 hours and 28 days after delivery because of the possible increased risk of uterine perforation and expulsion.

The safety of UPA during breastfeeding has not been studied, therefore, breastfeeding women should be advised not to breastfeed and to express and discard milk for a week after they have taken UPA.

Studies report no harmful or adverse effects on the infant or on breastmilk production, therefore, women are advised to continue to breastfeed after using LNG. 

Reference: FSRH Emergency Contraception: March 2017 (Amended December 2020)

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