Background Information

Overview of EC Methods

3 types of EC are currently licensed in the UK:

Method	Class	MoA	Timing	Effectiveness
Copper intrauterine device	Non-hormonal	Toxic to sperm and ova +/- Inhibit implantation	≤120 hours after UPSI or ovulation	>99%
Levonorgestrel (oral)	Progesterone	Delays ovulation (pre-LH surge only)	≤72 hours after UPSI	~85%
Ulipristal acetate (oral)	Progesterone receptor modulator	Delays ovulation (pre- and post-LH surge)	≤120 hours after UPSI	~98%

Guidelines

Choosing EC

Note that if UPSI occurred >5 days ago, and >5 days after the likely date of ovulation, emergency contraception is no longer considered effective.

1st line: Copper Intrauterine Device (IUD)

FSRH guidelines recommend always offering copper IUD as 1st line (if criteria met) – it is the most effective EC overall.

Criteria:

• UPSI ≤5 days ago, or up to 5 days after ovulation, and
• No contraindication (some important UKMEC 4 listed below)
  • Severe uterine distortion (e.g. large fibroids, congenital anomaly)
  • Unexplained vaginal bleeding
  • Current symptomatic pelvic infection (e.g. PID or purulent cervicitis)

2nd line: Hormonal Methods

2 oral hormonal emergency contraceptives are available: levonorgestrel and ulipristal acetate

Drug	Effective window	Contraindications
Levonorgestrel	UPSI within 72 hours (3 days) ago	Current breast cancer (use with caution)
Ulipristal acetate	UPSI within 120 hours (5 days) ago	Severe asthma controlled by oral steroids Breast / cervical / ovarian cancer Undiagnosed vaginal bleeding / uterine cancer NB that ulirpistal should be avoided if there is concurrent use of liver enzyme inducers (e.g. rifampicin, anti-epileptic drugs, St John’s wort)

There are no strict guidelines defining a universal first-line oral emergency contraceptive; the choice should be individualised, taking the following factors into account:

• Time since UPSI (effective window) and contraindications are the most important factors to guide the decision
• Ulipristal acetate has been shown to be more effective than levonorgestrel overall for emergency contraception (however, not universally mandated as 1st line)
• Ulipristal acetate is 1st line if UPSI occurred within the 5 days before ovulation (as levonorgestrel is less effective close to ovulation)
• Levonorgestrel may be considered for EC in individuals using regular COCP who have missed pills (when indicated, see the Contraception (Non-Emergency) article)
  • Ongoing hormonal contraception can be resumed immediately after using levonorgestrel
  • In contrast, hormonal contraception should be delayed for 5 days after using ulipristal acetate

Prescribing Consideration

Vomiting After EC

If vomiting occurs within 3 hours after taking oral EC (levonorgestrel / ulipristal acetate):

• Repeat dose ASAP
• Consider antiemetics if there is ongoing nausea

Obesity

1st line: copper intrauterine device if appropriate (unaffected by weight and BMI)

If BMI >26 kg/m² or weight >70kg:

• Offer double dose levonorgestrel (3mg), or
• Ulipristal acetate (normal dose)

Concurrent Use of Liver Enzyme Inducers

Liver enzyme inducers (e.g. rifampicin, carbamazepine, phenytoin, St John’s wort) can reduce the efficacy of oral contraceptives.

If current or past 28 days use of liver enzyme inducers:

• 1st line: copper intrauterine device
• 2nd line: levonorgestrel 3mg (off-label)
• Ulipristal acetate is NOT recommended

Repeat Use in Same Cycle

Both levonorgestrel and ulipristal acetate can be used more than once in the same cycle if needed:

• Using the same product is preferred if repeat EC is needed
• i.e. If levonorgestrel has been used before, use levonorgestrel again in the same cycle, instead of ulipristal acetate

Breastfeeding Women

1st line: copper intrauterine device

• FSRH notes a higher relative risk of uterine perforation during insertion than in non-breastfeeding women
• But the absolute risk (6 per 1,000) is low and it does not constitute a contraindication

2nd line: levonorgestrel

• Considered safe during breastfeeding
• Offer to optionally avoid breastfeeding for at least 8 hours after taking levonorgestrel to minimise exposure (but not strictly required)

Post-EC Care

Starting / Resuming Ongoing Contraception

EC method used	When to start hormonal contraception
Copper intrauterine device	Already provides ongoing contraception
Levonorgestrel	Can be started immediately (same day)
Ulipristal acetate	Start 5 days later (≥120 hours)

Pregnancy Testing After EC

Pregnancy testing is NOT routinely required after EC.

However, women should be advised to take a urine pregnancy test 21 days (3 weeks) after UPSI if any of the following:

• Next period delayed by >1 week
• Next period lighter / shorter than normal
• Unusual lower abdominal pain

References