How does a hormonal coil work?

The device sits inside the uterus and releases a small, steady amount of levonorgestrel, a progestogen. This makes cervical mucus thicker, creating a barrier that makes sperm movement more difficult. It also keeps the womb lining thin, so it is less prepared for pregnancy. Ovulation may be reduced in some users, but the main action is local in the uterus and cervix.

Periods often become lighter, shorter or less predictable after insertion. Spotting and irregular bleeding are common while the body adjusts. The coil does not protect against sexually transmitted infections, so condoms may still be needed for infection protection. It can also be used to reduce heavy menstrual bleeding when clinically suitable.

Follow the insertion advice you receive and check the threads as instructed if your clinician recommends this. Cramping and light bleeding can occur early on. Keep your follow-up plan, and record bleeding changes or pelvic discomfort. Tell the clinician about medicines, pregnancy possibility, pelvic infection symptoms or a history that could affect suitability before insertion.

Seek prompt medical advice for severe or increasing pelvic pain, fever, unusual-smelling discharge, very heavy bleeding, pain during sex or concern that the coil has moved. Get urgent help for severe pain with fainting, or if you think you may be pregnant while the coil is in place.

Ask how the coil will affect your periods, when contraception begins, how long it is intended to remain in place, what symptoms suggest movement or infection, and whether it may help heavy bleeding related to uterine fibroids.