First-lineellaOne

Ulipristal Acetate

Selective progesterone receptor modulator (SPRM)

EC up to 120 h post-UPSI; outperforms LNG late.

Oral

First-line for

  • Emergency contraception ≤120 h
  • Most effective oral EC near ovulation

Mechanism

Delays/inhibits ovulation by blocking progesterone-driven LH surge.

UPA vs LNG

  • UPA — up to 5 days, works closer to ovulation
  • LNG — 72 h only, less effective if BMI >26

Dosing

EC
30 mg PO single dose ≤120 h

Contraindications

  • AbsoluteSevere asthma on oral steroids
  • CautionBreastfeeding — express & discard ×7 days

Side effects

  • Headache, nausea, dysmenorrhoea
  • Cycle disturbance

Fetal & maternal notes

  • No evidence of teratogenicity if pregnancy ensues.

Key interactions

  • Progestogens (POP/COC)

    Avoid

    Mutual antagonism — wait 5 days before restarting hormonal contraception

  • Enzyme inducers

    Avoid

    ↓ efficacy → use Cu-IUD

Clinical pearls

  • 💡 Cu-IUD remains most effective EC overall.
  • 💡 Repeat pregnancy test if no period in 3 weeks.

Content last reviewed: REPLACE_ME (e.g. 2026-07)

Spotted something out of date? See our disclaimer or use Report an Error above.

For educational use only

Not medical advice. Verify dosing against the BNF and your local trust guidelines before prescribing.