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DCSRH · Core Wisdom · Clinical

Emergency contraception, decided

Dr Victoria Hammond
1 June 2026

Copper IUD, ulipristal or levonorgestrel? The decision turns on five variables you can hold in your head.

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Emergency contraception is one of the most reliably testable topics in the whole diploma, because the decision turns on a small number of variables you can actually hold in your head: how long ago, body weight, enzyme inducers, breastfeeding, and what they want to start next. Get those straight and most stems answer themselves.

Three options, in order of effectiveness

There are three methods, and they are not equal. Lead with effectiveness, then narrow by the practicalities.

Copper IUD (Cu-IUD) — the most effective by a distance. Can be fitted up to 5 days after the first episode of unprotected sex, or up to 5 days after the earliest expected ovulation, whichever is later. Works regardless of body weight and regardless of enzyme inducers. If they will accept a coil, it is the best answer.
Ulipristal acetate (UPA, 30 mg) — an oral option licensed up to 120 hours (5 days). More effective than levonorgestrel, particularly closer to ovulation, because it can still delay ovulation when the LH surge has begun.
Levonorgestrel (LNG, 1.5 mg) — oral, licensed up to 72 hours. The guideline doubles the dose to 3 mg if body weight is over 70 kg or BMI over 26, or if they are on an enzyme inducer.

Core Lens

The single most useful question is “where are they in the cycle?” Oral EC works by delaying ovulation, so it does nothing once ovulation has happened. That is exactly why the copper coil — which works after ovulation too — is the only option that stays fully effective late in the window.

The interactions that catch people out

UPA and progestogens fight each other. The guideline advises against UPA if she has used a progestogen in the last 7 days, and against starting (or restarting) hormonal contraception until 5 days after UPA — starting sooner blunts the UPA. LNG has no such wait: hormonal contraception can be quick-started straight away.
Enzyme inducers (e.g. carbamazepine, rifampicin, St John’s Wort) reduce oral EC. The Cu-IUD is the guideline’s first choice; if she declines, the CoSRH dose is LNG 3 mg (UPA is not recommended with enzyme inducers).
Breastfeeding: both are fine and neither needs an interruption. The old advice to express and discard for a week after UPA has been withdrawn — a January 2025 CoSRH statement, now in the emergency contraception guideline (amended April 2026), says no interruption of breastfeeding is necessary after a single dose — but older questions may still quote it.

Red flags & don’t-miss

The guideline expects the Cu-IUD to be offered for its efficacy, not just when oral EC is unsuitable, and a pregnancy and sexual-assault history to be taken. EC is a one-off — it’s the prompt to sort ongoing contraception, which is where the quick-start rules come in.

OTA pattern

Theory-paper stems love the edge cases: weight over 70 kg (LNG 3 mg), the woman who took her POP two days ago and now wants UPA (the guideline answer is LNG or a coil), and the “when can she start her pill?” follow-up (immediately after LNG; five days after UPA).

Victoria’s tip

I teach it as a flow: coil if she’ll have it → otherwise how many days? → UPA out to five, but check no recent progestogen and warn about the five-day wait → LNG if she wants to quick-start straight away, doubling the dose for weight or inducers. Four questions, and you’ve covered almost every stem.

Dr Victoria Hammond · MBBS, BSc (Hons) · Co-Founder & Lead for Educational Design

If you can recite that flow without looking, you’re ahead of most candidates — and you’ll handle it more calmly in clinic, too.