Emergency Contraception

Not required after unprotected sex occurring within 21 days postpartum or within 5 days of an abortion (already covered by the physiological/procedural contraceptive window).

Options, most to least effective

Method	Window	Effectiveness
Copper IUD	Within 5 days (120hrs) of unprotected sex, or within 5 days of the estimated earliest ovulation date	~99% — the most effective option, and provides ongoing contraception if left in situ
Ulipristal acetate 30mg (single dose)	Within 120hrs (5 days)	Most effective oral option — can delay ovulation even after the LH surge has started
Levonorgestrel 1.5mg (single dose)	TGA-approved to 72hrs; effective to 96hrs (efficacy beyond that uncertain)	Less effective than ulipristal or the copper IUD

Overall oral EC effectiveness is not precisely known — estimated to prevent ~85% of pregnancies that would otherwise occur. Levonorgestrel-releasing IUDs cannot be used for emergency contraception. No method is PBS-subsidised.

Choosing a method

Copper IUD is particularly preferred if the patient:

• Takes enzyme-inducing drugs
• Has BMI >30 or weighs >85kg (both oral options lose effectiveness at high weight — see below)
• Wants ongoing contraception from the same procedure

Weight/BMI and oral EC effectiveness

• Levonorgestrel: reduced effectiveness above BMI 26 or 70kg — consider a copper IUD, or a double dose (not TGA-approved, but the pragmatic option if a copper IUD isn’t accessible/wanted).
• Ulipristal: reduced effectiveness above BMI 30 or 85kg — copper IUD preferred; a double dose of ulipristal is not recommended.

Drug interactions and other cautions

• Both agents interact with enzyme-inducing drugs (reducing efficacy) — a copper IUD is the preferred alternative in this situation; if oral EC is still used, a double dose of levonorgestrel is reasonable but ulipristal dosing should not be doubled.
• Ulipristal is not recommended with oral corticosteroids.
• If any hormonal contraception (except an LNG-IUD) has been used in the past 7 days, or is started in the following 5 days, ulipristal may be less effective — this is why ongoing hormonal contraception must be delayed after taking it (see below).
• Vomiting within 3 hours of either dose — repeat the dose with an antiemetic.

Starting ongoing contraception afterwards

• After levonorgestrel: hormonal contraception can be started immediately (Quick Start).
• After ulipristal: wait 5 days before starting or restarting hormonal contraception, as progestogens may blunt ulipristal’s effect — use condoms in the meantime.

Follow-up

Recommend a pregnancy test:

• If the next period is >7 days late or lighter than usual (delayed/altered periods occur in ~18.5% of users — this is expected, not necessarily a sign of failure)
• 3 weeks after the last unprotected sex if EC has been used more than once in the same cycle
• 4 weeks after Quick Start (or 3 weeks if no further unprotected sex in the first week)