Key Facts

Emergency contraception prevents pregnancy after unprotected sexual intercourse (UPSI) or contraceptive failure. Three options are available in the UK: oral levonorgestrel, oral ulipristal acetate, and the copper intrauterine device. The copper IUD is the gold standard due to its superior efficacy.

Epidemiology

• Approximately 5-8% of women of reproductive age use EC each year in the UK
• Demand peaks in January and after bank holidays
• Most commonly requested by women aged 16-24 years

Aetiology

• Not applicable (preventive measure)

Pathophysiology

• Levonorgestrel: primarily delays or inhibits ovulation by suppressing the LH surge; no effect if ovulation has already occurred
• Ulipristal acetate: selective progesterone receptor modulator; delays ovulation even after the LH surge has begun (more effective timing window)
• Copper IUD: toxic to sperm and ova; prevents fertilisation; may also prevent implantation; effective pre- and post-ovulation

Consultation Approach

• Time since UPSI (determines method options)
• Date of last menstrual period and cycle length
• Other episodes of UPSI in this cycle
• Current medications (enzyme inducers)
• Ongoing contraceptive needs (bridging to regular contraception)

Red Flags

• UPSI >120 hours ago: no effective EC available (discuss pregnancy testing)
• Symptoms of existing pregnancy: perform pregnancy test before EC
• Signs of sexual assault: sensitive enquiry, safeguarding, referral to SARC

Bedside

• Pregnancy test (if >3 weeks since UPSI or if period is late)
• Sexual health risk assessment
• Assess for contraindications to chosen method

Bloods

• Not routinely required
• STI screening as appropriate

Imaging

• Pelvic USS only if IUD insertion technically difficult or malposition suspected

Special Tests

• Chlamydia/gonorrhoea screening if IUD insertion planned (can be done at time of insertion with prophylactic azithromycin if results pending)

Non-pharmacological

• Copper IUD insertion: most effective EC; can be inserted up to 5 days after UPSI or up to 5 days after earliest estimated ovulation
• Also provides ongoing contraception (5-10 years)
• Requires trained provider; can be performed in sexual health clinics, GP surgeries, or A&E

Pharmacological

• Levonorgestrel (Levonelle) 1.5mg PO single dose:
  • Effective up to 72 hours; efficacy decreases with time (95% within 24h, 85% 24-48h, 58% 48-72h)
  • Double dose (3mg) if taking enzyme-inducing drugs
  • Can quick-start hormonal contraception immediately after
  • Available OTC from pharmacies
• Ulipristal acetate (EllaOne) 30mg PO single dose:
  • Effective up to 120 hours; maintains efficacy better than levonorgestrel over time
  • Do NOT start hormonal contraception for 5 days after (progesterone receptor modulation)
  • Not to be used if already taking hormonal contraception in same cycle (reduced efficacy)
  • Available OTC from pharmacies

Surgical/Interventional

• IUD insertion as above
• No other surgical interventions

Referral Criteria

• If IUD requested but not available at presenting service: refer to sexual health clinic within 5 days
• Safeguarding referral if under 16 or concerns about sexual exploitation/assault
• Follow-up pregnancy test at 3 weeks if period does not arrive
• Bridging to ongoing contraception: all women should be offered regular contraception at the EC consultation

• Copper IUD: pregnancy rate <0.1% (>99% effective)
• Ulipristal: pregnancy rate ~1-2% (98% effective)
• Levonorgestrel: pregnancy rate ~2-3% (84-95% effective depending on timing)
• No long-term fertility effects from oral EC
• Side effects of oral EC: nausea (levonorgestrel 14%, ulipristal 12%), headache, irregular bleeding
• If EC fails: no evidence of teratogenic effects on established pregnancy

Emergency Contraception Comparison