Hormonal IUD: definition and meaning
A hormonal IUD (intrauterine device, also called an IUS or hormonal coil) is a small T-shaped device placed in the uterus that slowly releases levonorgestrel, a progestin. It thickens cervical mucus and thins the uterine lining. It's over 99% effective as contraception and lasts 3 to 8 years depending on the brand. It's also a treatment for heavy periods.
How it works and what changes
The progestin acts mainly inside the uterus, so blood levels are low. Many people still ovulate, so cycles and hormonal mood patterns often continue, even if bleeding changes a lot.
| Time with the IUD | Bleeding often |
|---|---|
| First 3 to 6 months | Irregular spotting or breakthrough bleeding |
| After 6 to 12 months | Much lighter periods |
| Longer term | About 1 in 5 stop bleeding altogether (higher-dose devices) |
Why it matters
- Very effective, long-acting and reversible: fertility returns soon after removal
- First-line treatment for heavy menstrual bleeding
- Can ease pain from endometriosis and adenomyosis
- Used to protect the lining during estrogen HRT
Possible side effects include spotting, acne, breast tenderness and headaches. Some people report mood changes; research is mixed, and if your mood drops after insertion it's worth telling your doctor. Because you may still ovulate, tracking mood and symptoms can show you still have a cycle even without periods. See birth control and mood.
Contact a doctor if you can't feel the threads or feel the plastic, have severe pelvic pain, fever or unusual discharge, very heavy bleeding, or a positive pregnancy test with an IUD in place.
Frequently asked questions
Do you still ovulate with a hormonal IUD?
Many people do, especially with lower-dose devices. That's why some still notice PMS and mood patterns.
Is a hormonal IUD the same as a copper IUD?
No. A copper IUD has no hormones and can make periods heavier; a hormonal IUD usually makes them lighter.
Sources
This page is for information only and isn鈥檛 medical advice. If something worries you, please talk to a doctor.
Keep reading
Birth control and mood: can the pill cause mood swings?Birth control mood swings, anxiety and depression: what research shows, why some people feel better and others worse, and how to track it before you decide.
Progestin: definition and meaningA progestin is a synthetic hormone that acts like progesterone, used in birth control and hormone therapy. Types, how they work, and effects on mood.
Heavy menstrual bleeding: definition and meaningHeavy menstrual bleeding (menorrhagia) is period bleeding that disrupts daily life. Signs your flow is heavy, common causes, and when to see a doctor.Combined contraceptive pill: definition and meaningThe combined contraceptive pill contains estrogen and a progestin to stop ovulation. How it works, why pill bleeds aren't real periods, and mood effects.Breakthrough bleeding: definition and meaningBreakthrough bleeding is unscheduled bleeding while on hormonal birth control. Why it happens, how long it lasts, and when it's worth seeing a doctor.