Copper IUD (Paragard): what it treats, how it is used, side effects
Last updated September 3, 2026.
The copper IUD (brand name Paragard) is the only hormone-free intrauterine device, effective for up to 10 years. Copper ions make the uterus hostile to sperm, with no hormones involved at all, and inserted within 5 days of unprotected sex it is also the most effective emergency contraception available.
What does it treat?
It prevents pregnancy, over 99% effectively, for up to a decade, with nothing to remember daily. It is the go-to for people who cannot or prefer not to use hormones: no blood-clot risk from estrogen, no mood or libido effects from progestins, and it is fully compatible with breastfeeding. It does not lighten periods; if anything, the opposite.
How do you take it?
A clinician inserts it in an office visit lasting minutes; cramping during and after placement is expected, and a pre-visit pain reliever helps. Protection starts immediately, including as emergency contraception within 5 days of unprotected sex. You check the strings monthly, and removal is a quick office procedure whenever you want it out or at the 10-year mark. Periods arrive on their natural cycle throughout.
Side effects to know
- Common: heavier and longer periods, more cramping, and spotting between periods, worst in the first months and usually easing within 6 to 12; anemia is a real consideration for people who start with heavy periods.
- Serious: expulsion, embedment or perforation (rare), pelvic inflammatory disease in the first weeks, and if pregnancy occurs with it in place, a higher share are ectopic.
Who should not take it?
Not with Wilson's disease (the body cannot clear copper), current pelvic infection, unexplained vaginal bleeding, uterine or cervical cancer, a uterus distorted by fibroids, or a copper allergy. If your periods are already heavy and crampy, the copper IUD can make that meaningfully worse, and the levonorgestrel IUD is usually the better match. It is MRI-safe under stated conditions.
When is it an emergency?
Call 911 for severe lower abdominal pain with fever, fainting, or very heavy bleeding. New severe pelvic pain with a positive pregnancy test is a same-day ectopic-pregnancy evaluation. Missing strings with pain also gets checked promptly. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
What a Pymander AI doctor consult looks like
Illustrative example, not a real member's messages.
Common questions
How can a piece of copper prevent pregnancy with no hormones?
The copper slowly releases ions that disable sperm: they move poorly and survive badly in the uterus, so fertilization essentially never happens. Because it works before implantation through sperm toxicity, it also works retroactively as emergency contraception within 5 days of unprotected sex, better than any pill.
Will the copper IUD make my periods worse?
For most users, heavier, longer, and crampier, especially in the first 6 months, then easing toward a new normal. If your periods are already heavy, that trade may not be worth it, and the hormonal IUD (which lightens periods) is usually the better pick. If periods stay light on it, you are in the lucky half.
How long does Paragard last?
Up to 10 years per the label, with no maintenance between annual check-ins and your own monthly string checks. Removal is quick whenever you want, and fertility returns immediately.
Can I feel it, or can a partner feel it during sex?
You should not feel the device itself. The strings hang a short way into the vagina and soften over weeks; partners occasionally notice them early on, and the clinic can trim them if they are pokey. Feeling the hard plastic itself means it has moved, and that needs a check.
Is the copper IUD safe while breastfeeding?
Yes. No hormones means nothing passes to milk, which is why it is the standard recommendation for breastfeeding parents who want long-acting contraception. Insertion timing after delivery is planned with your clinician because of slightly higher expulsion and perforation rates in the postpartum window.
What is Wilson's disease and why does it rule this out?
Wilson's disease is a rare genetic condition where the body cannot excrete copper, letting it accumulate to toxic levels in the liver and brain. Adding a copper-releasing device on top of that is a clear no. It is the one copper-specific contraindication, and the label lists it explicitly.