When we choose a contraceptive method there are many factors to take into account, and without a doubt one of the most important is its effectiveness. Knowing that we are choosing a safe contraceptive helps us plan our sexual life with stability and regulate the menstrual cycle, being one of the main reasons why more and more women decide on the IUD. The effectiveness of the IUD is widely proven, the margin of error is between 0.4 and 2.5% in the copper IUD, and only 0.1% in the case of the Mirena IUD, far exceeding most of the alternatives such as the condom or the contraceptive pill, since once inserted there are very few cases in which the IUD fails, and its continued use can be maintained for between three and five years depending on the model.

How to detect the loss of effectiveness of the IUD

  • The IUD is a small T-shaped device that is placed inside the cervix, preventing the union of the egg and sperm. In addition, in the case of the Mirena IUD, the release of hormones helps promote protection while regulating the menstrual cycle and reducing bleeding, which is why it is especially indicated in cases of hypermenorrhea.
  • Being placed in the uterus, it is not necessary to carry out any routine beyond regularly checking that the IUD has not moved. This is one of the main reasons that support its effectiveness, since it is not susceptible to breaking as easily as the condom or the diaphragm, and it does not require the effort of remembering to apply it daily or monthly as it happens in the case of the pill or the contraceptive ring.
  • The effectiveness of the IUD only decreases if there are contraindications, in which case its use is not recommended. Some of these situations are suffering from a pelvic infection, uterine cancer, suspicion of pregnancy, etc., which should be consulted with a doctor or gynecologist so that he can carry out the necessary tests before authorizing it.
## How to choose the right IUD for you: copper vs hormonal (actionable guidance) Choosing between a copper IUD and a hormonal IUD (levonorgestrel-releasing, e.g., Mirena, Kyleena, Skyla) is one of the most important decisions when considering intrauterine contraception. Below I provide a practical, step-by-step approach I use in clinic to help patients choose—and the real-world considerations that matter. - Step 1 — Define your priorities - Do you want the lightest possible periods or to stop bleeding altogether? Consider a levonorgestrel IUD (Mirena is most effective at reducing bleeding). - Do you prefer a hormone-free method or are you breastfeeding/avoiding systemic hormones? Consider a copper IUD. - Are you sensitive to hormonal side effects (mood changes, acne, breast tenderness)? If yes, copper may be preferable. - Are you comfortable with possible heavier menstrual bleeding initially or permanently? Copper IUDs can increase bleeding and cramping, especially in the first 3–6 months. - Step 2 — Match device options to anatomy and life stage - Nulliparous (no prior vaginal birth): Smaller devices (Skyla, Kyleena) or careful insertion technique can reduce discomfort. Mirena is still commonly used and effective. - Parous (vaginal birth): Most devices are suitable. - Immediate postpartum contraception: Both copper and hormonal IUDs can be placed immediately after delivery—useful when follow-up is uncertain—though expulsion rates are higher with immediate insertion (weigh pros/cons). - Desire for future pregnancy: IUDs are fully reversible; fertility typically returns quickly after removal—this is true for both types. - Step 3 — Consider bleeding and cramping profiles (practical expectations) - Mirena (levonorgestrel 52 mg): Most commonly reduces bleeding; up to 20–50% of users report amenorrhea at 1 year. Very useful for menorrhagia. Spotting and irregular bleeding are common in the first 3–6 months. - Skyla/Kyleena (lower-dose levonorgestrel): May reduce bleeding but less dramatically than Mirena; often chosen for younger or nulliparous patients. - Copper IUD (e.g., ParaGard): No hormones. Can cause heavier, longer periods and increased cramping for some people for several months after insertion; many tolerate it well, but those with baseline heavy bleeding are less satisfied. - Step 4 — Discuss side effect management before insertion - Pain control: Take 400–600 mg of ibuprofen 30–60 minutes before insertion if you have no contraindication. Consider local anesthesia or paracervical block if anxious or if your clinician suggests it. - For cramping after insertion: Regular NSAIDs (ibuprofen or naproxen) for 24–72 hours can be sufficient. If cramping persists beyond a week, contact your provider. - Expect irregular spotting for the first 3 months (hormonal IUD) or heavier periods for 1–3 cycles (copper). - Real-world example - Case: Maria, 34, has heavy, painful periods and wants reliable contraception. She chose Mirena after counseling. Within three months her bleeding decreased markedly; by 6–12 months she had very light periods and improved quality of life. She required no further interventions. - Practical takeaways: If you value reduced bleeding and can tolerate the initial months of spotting, Mirena is often the best choice. - Actionable checklist to bring to your appointment - Summary of your contraception priorities (avoid hormones, reduce bleeding, long-term, immediate postpartum, etc.) - Medical history (previous PID, current pelvic infection symptoms, allergy to copper, desire for pregnancy) - List of current medications (some interact with systemic hormones; IUDs are minimally affected) - Insurance or cost considerations—ask your clinic about device coverage and insertion fees; many programs cover IUDs fully. - Bring a support person if you prefer during insertion. ## Insertion, follow-up, and managing complications (actionable expert-level care) Insertion and follow-up are critical to maximize safety and maintain effectiveness. Below I outline the stepwise process I recommend and the exact actions you and your clinician should take if something feels off. - What to expect at insertion (practical timeline) - Pre-visit: Complete STI screening if at risk (chlamydia/gonorrhea), review medications, and confirm you are not pregnant. - Day of appointment: The procedure takes 5–10 minutes for most people. - You will be placed in the lithotomy position. - A speculum is used, cervical visualization is performed, and the cervix may be cleaned with antiseptic. - The clinician measures uterine depth with a sound (this can feel crampy). - The IUD is loaded and inserted through the cervix into the uterus; strings are trimmed to a safe length. - Immediately after insertion: Expect cramping and possible light bleeding. Rest for 10–20 minutes in the clinic if needed. - Pain control (practical tips) - Take 400–600 mg ibuprofen 30–60 minutes before the appointment unless contraindicated. - Consider a topical anesthetic or paracervical block if you have severe anxiety or expect increased pain. - Use heat and NSAIDs after the procedure for cramp relief. - If you have a known difficult cervix, discuss pre-medication or cervical priming (misoprostol is used in some settings but is not routine everywhere and may have side effects). - Follow-up schedule I recommend - Self-check at 4 weeks: You should be able to feel the strings—do not pull on them. If you cannot feel them or feel plastic, contact your clinic. - Clinic visit at 4–12 weeks: Many providers arrange one check, especially if symptoms are present. An ultrasound is reserved for suspected expulsion, malposition, or pregnancy. - Annual check: Verify strings and discuss ongoing satisfaction and side effects at routine gynecology visits. - How to check strings safely (step-by-step) - Wash your hands thoroughly. - Sit or squat and insert one finger into the vagina to the level of the cervix. - Gently feel for thin strings coming from the cervical os. They should be soft and not protrude far. - If you cannot find them, do not poke repeatedly—call your provider for evaluation. - Common complications and exact actions - Expulsion (device partially or completely comes out): Occurs in about 2–10% overall, higher in immediate postpartum insertions and in younger/nulliparous people. Action: If you suspect expulsion (you feel the IUD or strings are much longer or you find the device), use backup contraception (condoms) and see your clinician immediately. Re-insertion is possible. - Perforation (rare): Approximately 1 per 1,000 insertions; may occur during insertion if the uterus is inadvertently pierced. Action: If you have severe pain during insertion that does not resolve, fever, or persistent severe pain, seek urgent care. Imaging (ultrasound/X-ray) will localize the device; surgical retrieval may be necessary. - Infection: Risk of pelvic inflammatory disease is slightly increased in the 20 days after insertion if STI is present at insertion; long-term risk is low. Action: If you have fever, severe pelvic pain, foul-smelling discharge—seek prompt evaluation. Diagnosis and antibiotics are indicated; sometimes removal is necessary if infection does not respond. - Pregnancy with IUD in place: Rare, but when it occurs, there is higher risk of ectopic pregnancy. Action: If you miss a period and pregnancy is suspected, get a pregnancy test immediately. If positive, contact your clinician: many times the pregnancy must be evaluated and the IUD removed if strings are visible. - Real example with actionable plan - Case: Sofia had a copper IUD placed immediately after cesarean delivery because she could not return reliably for follow-up. At her 6-week check she reported heavy lochia initially but then an episode of severe cramping and saw the device in a pad. This is classic expulsion. Action taken: She used condoms and called the clinic, had a pelvic exam and ultrasound confirming expulsion, and chose to have a new device inserted after counseling about higher expulsion risk with immediate postpartum insertion. - What to do if you suspect the IUD is not working - Use backup contraception immediately (condom). - Avoid intercourse or use condoms until evaluated if you suspect expulsion or missing strings. - Arrange an urgent visit: exam and ultrasound to confirm IUD position. - If pregnancy is confirmed despite IUD, see your clinician urgently for counseling and management. ## How the IUD compares with other methods — practical perspective - Effectiveness (typical-use failure rates per year) - Levonorgestrel IUDs: ~0.1% (very low). - Copper IUD: ~0.4–2.5% depending on model and study—still <1% to ~2% in many series. - Combined oral contraceptives (the pill): ~7% typical-use failure. - Male condom: ~13% typical-use failure. - Why this matters: IUDs remove user error (no daily pill or correct condom use required). For many patients who struggle with adherence, the IUD provides consistent protection. - When IUD may be less appropriate - Current pelvic infection (untreated chlamydia/gonorrhea). - Known or suspected pregnancy. - Certain uterine anomalies or large fibroids that significantly distort the uterine cavity. - Active cervical or uterine cancer. - Allergy to copper (for copper IUD). - Practical counseling points I give patients - IUDs do not protect against sexually transmitted infections. Use condoms if STI risk is present. - Decide together based on bleeding patterns, tolerance of hormones, plans for future pregnancy, and comfort with the insertion procedure. - Discuss removal plan: The IUD can be removed quickly in clinic; fertility generally returns rapidly. ## Cost, access, and practical tips for minimizing barriers - Cost considerations - The upfront cost of an IUD (device + insertion) can be high, but when amortized over its lifespan it is often cost-saving compared with monthly contraception. - Many insurance plans and public health programs cover the cost; ask your clinic about coverage, sliding scale fees, or family planning programs. - If cost is a barrier, ask about same-day insertion programs or partnerships with local clinics. - Access and timing - If you want contraception immediately (e.g., post-abortion, post-delivery, or after stopping pills), discuss same-day insertion. Many clinics offer immediate intrauterine device placement. - For those with irregular schedules, flexible scheduling and walk-in clinics can increase access. - Practical preparation for your appointment - Bring snacks and a bottle of water—lightheadedness can occur after insertion. - Wear comfortable clothing; a heating pad or warm shower afterward helps cramps. - Arrange a ride home if you’re anxious or have significant fainting risk during procedures. [related topic](/blog) — see our broader contraceptive options and counseling posts for more on method selection. If you prefer IUD-friendly products, check our [shop](/shop) for recommended items like heat packs, NSAID dosing charts, and post-insertion care kits. ## FAQ ### Can an IUD cause infertility? No. The IUD itself does not cause long-term infertility. The historical concern came from infections (e.g., untreated chlamydia or gonorrhea) that sometimes led to pelvic inflammatory disease (PID), which can damage the fallopian tubes and affect fertility. Modern screening and sterile insertion techniques reduce this risk substantially. If an infection is present at the time of insertion, there is a small increased short-term risk of PID. Actionable advice: if you are at risk for STIs, get screened and treated before insertion or use condoms until screening is complete. Fertility typically returns quickly after removal of either a copper or hormonal IUD. ### What are the signs that the IUD is not in place or might have failed? - You can feel the IUD (the plastic T) in the vagina or on a pad—this indicates expulsion. - You notice that the strings feel different (much longer or shorter) or you cannot locate the strings when you previously could. - You have new, unusual pelvic pain or heavy bleeding beyond your normal pattern. - You suspect pregnancy (missed period, positive pregnancy test). Action: use condoms and seek prompt evaluation—your clinician will do a pregnancy test and ultrasound and decide whether the IUD should be removed. ### What should I do if I want to get pregnant after having an IUD? Plan removal with your clinician at a convenient time. Fertility returns quickly after removal—most people conceive within months if there are no other fertility issues. Actionable advice: if you are trying to conceive, have a preconception visit to discuss folic acid supplementation, STI screening, and timing of IUD removal to match ovulatory cycles if desired. ### Is it safe to use an IUD while breastfeeding? Yes. Both copper and levonorgestrel IUDs are considered safe during breastfeeding. Many major guidelines support IUD use postpartum, including immediate postpartum insertion in many settings. The levonorgestrel IUD releases very low systemic hormone levels and has not been shown to affect milk production significantly. Action: If you have had a cesarean or complicated delivery, discuss timing; some clinicians recommend waiting a few weeks while others will place the device immediately in the delivery room. ### How common are complications like expulsion, perforation, and infection—and what should I do? - Expulsion: occurs in approximately 2–10% of users overall; higher in immediate postpartum insertions and younger patients. If you suspect expulsion, use condoms and seek evaluation for re-insertion if desired. - Perforation: rare (~1 per 1,000 insertions). Severe pain during insertion warrants immediate evaluation; if suspected, imaging will locate the device and removal may require surgery. - Infection: risk of PID is low but slightly elevated in the first 20 days if STI is present at insertion. If you develop fever, severe pelvic pain, or foul discharge, seek prompt care. Early antibiotic treatment is typically effective; rarely the IUD must be removed. --- If you would like, I can add a printable checklist to take to your clinic visit or a sample list of questions to ask your provider when considering an IUD.