Ulipristal acetate: A new oral emergency contraception option

Since the introduction of ulipristal acetate (UPA) in April 2016, Australian women have three emergency contraception (EC) options:

  • 1.5mg levonorgestrel (LNG-EC) available without a prescription at pharmacies; licensed for use up to 72 hours after unprotected intercourse but with evidence for effectiveness up to 96 hours
  • 30mg UPA available by private prescription; licensed for use up to 120 hours after unprotected intercourse with proven effectiveness across the 5-day time frame
  • Insertion of a copper IUD within 5 days of unprotected intercourse.

What is UPA?

UPA is a selective progesterone receptor modulator. It works in a similar way to LNG-EC by preventing or delaying ovulation until sperm are no longer viable in the female reproductive tract. UPA can prevent ovulation even as late as the luteinising hormone (LH) surge, unlike LNG-EC which has no effect once the LH surge has begun.

How effective is UPA?

A meta-analysis of two randomised trials showed reduced risk of pregnancy in women treated with UPA compared with LNG-EC. The effect was strongest when UPA was taken within 24 hours (odds ratio 0·35 p= 0·035) but a reduction also occurred when UPA was administered up to 120 hours after unprotected intercourse1. UPA may be more effective than LNG-EC for women with a high BMI > 30 kg/m2 although evidence is limited.

Are there any contraindications or precautions?

UPA has few contraindications or precautions. These include allergy, severe asthma treated by oral glucocorticoids and severe liver disease. Available evidence does not show risk of harm to a continuing pregnancy or fetus if taken inadvertently during early pregnancy.

Breastfeeding women are advised to express and discard breastmilk for one week after administration of UPA. Breastfeeding women can use the LNG-EC and continue to breastfeed.

What drug interactions occur with UPA?

UPA is not recommended for women using liver enzyme-inducing medications due to reduced efficacy. Women taking liver enzyme inducing medications can be advised to use the LNG-EC at a doubled dose (off license).

As a result of its effect on the progesterone receptor, administration of a progestogen-containing contraceptive method within five days of UPA also appears to reduce its effectiveness (this includes the combined pill, vaginal ring, progestogen-only pill, implant, depo injection but not the levonorgestrel IUD). Women starting one of these contraceptive methods and those using EC as a result of missed contraceptive pills are advised to delay initiation for five days after UPA administration (women will additionally then need to use condoms or abstain from intercourse until the method becomes effective). No delay is required for LNG-EC. UPA should not be used concurrently with LNG-EC.

What is the side-effect profile of UPA?

The side-effect profile is similar to LNG-EC with a small percentage of women experiencing nausea, headache and other hormonally-related symptoms. Most women experience bleeding within 7 days of the expected time but 20% experience bleeding more than 7 days later than expected. Women should be advised to perform a urine pregnancy test or see their doctor if their period is more than 7-10 days late, lighter than usual or unusual in any way. It is important that women understand that UPA can fail and that they do not mistake an implantation bleed for their period.

UPA is currently only available by private prescription, and is likely to be more expensive than LNG-ECP.

An updated factsheet on EC options is available on the Family Planning NSW website.

 

Article submitted by Dr Deborah Bateson, Medical Director Family Planning NSW