Updated by the Progyny Clinical Team — June 2025.
IUI is a type of fertility treatment. It helps sperm get closer to the egg during ovulation, which may improve the chances of pregnancy.
Many IUI cycles use medicines to help the body grow eggs and time ovulation. If you don’t ovulate regularly, your fertility provider may call this “ovulation induction.” If you do ovulate regularly, it’s called “ovarian stimulation.” In both cases, your provider will check you closely to see how your body is responding.
Your fertility team wants to give you the best chance of success while keeping you safe. It’s important to understand the risks of treatment, and why your IUI cycle may need to be canceled in some cases.
Your provider may give you either pills or injections to help your ovaries grow one or more eggs. These medicines are used in both ovulation induction and ovarian stimulation.
Oral medicines (pills):
Injectable medications:
Gonadotropins are often used for in vitro fertilization (IVF), but sometimes in IUI cycles at lower doses.
IUI success rates vary, but are usually around 15-20% per cycle, depending on your age and diagnosis.
The main risk is multiple pregnancy, meaning twins or more, if more than one follicle grows. While more follicles can increase your chances of getting pregnant, they also raise the chance of carrying twins or higher-order multiples, which have more risks for both the pregnant person and the babies.
Risk by medication type:
Triplets or more happen in about 2% of IUI cycles, depending on your age and how many follicles you grow.
Studies show that once more than two to three follicles grow, your chance of having a healthy single pregnancy doesn’t go up much, but your risk of a multiple pregnancy goes up a lot. That’s why your provider may recommend canceling your IUI cycle if too many follicles grow.
Carrying twins, triplets, or more increases the risk of problems for both you and your babies.
Risks for the pregnant person:
Risks for the babies:
The more babies there are, the higher the risk. Some patients who become pregnant with triplets or more may choose a procedure called selective reduction (for example, reducing triplets to twins). This can lower the chance of serious complications, but it comes with risks and is a deeply personal decision. Your fertility team can support you through this process.
If you grow more than three follicles, your provider will talk to you about the risk of multiples. If the risk is too high, your IUI cycle may be canceled. If that happens, you should avoid intercourse during your fertile window to lower the chance of getting pregnant with multiples. You’ll try again in your next cycle, possibly with a lower medication dose.
Some people choose to move on to IVF instead. IVF lets you grow multiple eggs, make embryos, and then choose the healthiest one to transfer. It’s a safer way to try for one baby, as only a single embryo is placed in the uterus. While one embryo can still split into identical twins, the overall risk of multiples is much lower than with IUI.
Your fertility team wants to help you get pregnant in the safest way possible. Sometimes that means canceling a cycle to avoid risks. While this can be disappointing, it’s done with your health in mind.
Talk openly with your provider about your treatment plan, risks, and all your options. They’re there to help you make the best decisions for your unique situation.
If you have questions or concerns, 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.