Updated by the Progyny Clinical Team — August 2025.
Intrauterine insemination (IUI) is a type of fertility treatment. It involves placing a concentrated sample of sperm directly into the uterus to help increase the chances of pregnancy.
Before the procedure, the sperm sample is washed in a lab to remove non-moving sperm and other fluids. What’s left is a small, active sample of healthy sperm. This sample is placed into a thin tube called a catheter, which is attached to a syringe.
Around the time of ovulation, you go to the clinic and lie on an exam table with your feet in stirrups, like during a Pap smear. A member of your fertility care team uses a speculum to see the cervix. Next, they gently guide the catheter through the cervix into the uterus and release the sperm. The goal is to get the sperm closer to the fallopian tubes, where the egg is traveling. If fertilization happens, a pregnancy test about two weeks later will confirm the result.
Success rates for IUI vary, but cumulative pregnancy rates may reach 15% to 20% after three cycles. IUI is often chosen because it’s low risk, has minimal side effects, and doesn’t require surgery. Your doctor may recommend IUI based on your specific situation.
Most IUI cycles include medications to improve success rates, but sometimes an unmedicated cycle is the better choice.
Unmedicated IUI cycle
In an unmedicated cycle, no hormones or fertility drugs are used. This is usually for people who ovulate on their own and have regular menstrual cycles.
Ovulation is either tracked at home using ovulation predictor kits or by ultrasound in the clinic around day 10 to 12 of the cycle. The IUI is scheduled based on when ovulation is expected — either after a natural luteinizing hormone (LH) surge or after a human chorionic gonadotropin (hCG) shot to trigger ovulation. The insemination usually happens 24 to 36 hours later.
Unmedicated cycles don’t significantly improve pregnancy chances for people or couples using sperm from a partner, but they may help if they’re using donor sperm.
Medicated IUI cycle
In a medicated cycle, prescription medications are used to help the ovaries grow eggs. This can help people who don’t ovulate regularly and may improve success rates for those who do.
Common medications:
- Letrozole is often used for people with irregular periods. It blocks an enzyme that helps make estrogen, which tricks the brain into sending out more follicle-stimulating hormone (FSH). This hormone helps a follicle with an egg grow.
- Clomiphene citrate (Clomid) is often used for people with regular cycles. It works by blocking estrogen in the brain, which also causes the brain to release more FSH.
Injectable fertility drugs used to be more common, but they carry a higher risk of multiple births. Today, they’re only used in special cases.
How medications are used
Letrozole and Clomid are taken as pills for five days, usually at the beginning of the cycle when hormone levels are low. Blood work may be used to check hormone levels in people with irregular periods.
After finishing the medication, you may track your LH surge at home using ovulation predictor kits. You could also go to the clinic for an ultrasound to check follicle growth. A follicle is a tiny bubble-like structure in your ovary that helps an egg grow and get ready to be released so pregnancy can happen.
Once the follicle is the correct size on ultrasound or an LH surge is found with bloodwork in the clinic or urine testing at home, you may receive an hCG trigger shot. This shot helps start or boost ovulation. The IUI is typically scheduled 24 to 36 hours later.
Risks of medication with IUI
The biggest risk of using fertility medications with IUI is having a multiple pregnancy, such as twins or triplets. Since the body makes its own FSH, it’s hard to control how many eggs are released. If more than one egg is fertilized, it can lead to a higher-risk pregnancy.
- Multiple pregnancies can increase the risk of:
- High blood pressure
- Preeclampsia
- Gestational diabetes
- Caesarean section
- Preterm birth
- Breathing or brain issues in babies
If an ultrasound shows too many follicles growing, your doctor may cancel the cycle to avoid these risks. Your fertility care team will help you balance your chance of success with your overall health and long-term family goals.
If you have questions, Progyny is here for you. Please contact your Progyny Care Advocate for support.
Disclaimer: The information provided by Progyny is for educational purposes only and is not medical advice. Always consult a qualified healthcare provider for medical guidance.