Emergency contraception: copper intrauterine device first
Emergency contraception is used after unprotected intercourse, and UK guidance is to offer the copper intrauterine device (a small T-shaped device placed in the womb) first.
Remember
When the patient will accept it, offer the copper intrauterine device (the copper coil) first for emergency contraception: it is the most effective emergency method, can be fitted up to 120 hours after unprotected intercourse (or up to 5 days after the earliest expected ovulation), and can stay in as ongoing contraception.
After unprotected intercourse, three options are licensed in the UK, and the copper intrauterine device (the copper coil, a small T-shaped device that a trained nurse or doctor places in the womb) is the one to offer first. The Faculty of Sexual and Reproductive Healthcare gives the reason as its superior efficacy, with oral options as alternatives where a coil cannot or will not be used.
Copper ions are toxic to sperm and to the egg and may also prevent implantation (a fertilised egg embedding in the womb lining), so the coil does not rely on delaying ovulation (the release of an egg from the ovary). A single act of intercourse carries roughly a 5% risk of pregnancy with regular cycles, but around 20 to 30% when it falls at mid-cycle.
The coil can be inserted up to 120 hours (5 days) after unprotected intercourse, or up to 5 days after the earliest expected ovulation. When cycle dates are unknown, ovulation cannot be timed, and the extra allowance after the earliest expected ovulation only helps when ovulation can be estimated, so the simple rule is to count the 120 hours from the intercourse itself.
Levonorgestrel (one of the two emergency pills) is licensed up to 72 hours and works by delaying or inhibiting ovulation, so it is ineffective once ovulation has occurred. Ulipristal acetate (the other emergency pill) is licensed up to 120 hours and can delay ovulation even after the luteinising hormone (LH) surge (the hormone spike that triggers ovulation) has begun, but it is still less effective than the coil.
Of the emergency methods, only the coil offers ongoing contraception once inserted. An emergency pill is a single dose.
Key facts
- Most effective
- the copper intrauterine device is the most effective emergency method, with an overall pregnancy rate of less than 0.1%.
- Coil time limit
- it can be inserted up to 120 hours after unprotected intercourse, or up to 5 days after the earliest expected ovulation.
- Levonorgestrel
- licensed up to 72 hours, it works by delaying or inhibiting ovulation, and its efficacy declines with time after intercourse.
- Ulipristal acetate
- licensed up to 120 hours, it is more effective than levonorgestrel, particularly close to ovulation, but less effective than the coil.
- After ulipristal
- hormonal contraception is avoided for 5 days afterwards because it can blunt the effect.
- Ongoing cover
- once inserted, the coil is the only emergency method that also offers ongoing contraception.
Exam traps
- Levonorgestrel is licensed in the UK only up to 72 hours, and because it works by delaying ovulation it is unlikely to help when ovulation is close.
- Simply starting a combined pill (a tablet containing oestrogen and a progestogen) is not a recognised way to prevent pregnancy from sex that has already happened, because it protects against future sex when it is taken regularly.
- A contraceptive injection into a muscle gives long-acting contraception for future sex, which makes it tempting, but it is not one of the recognised emergency methods, since the NHS lists only the coil and the emergency pill.
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