For a woman to become pregnant naturally, her partner’s sperm must travel from the vagina through the cervix to the uterus and then into one of the fallopian tubes. If the sperm reaches a tube shortly after ovulation, it may encounter an oocyte (egg) and cause fertilization.

Intrauterine insemination (IUI) is a procedure used to increase a woman’s chances of getting pregnant. In IUI, the partner's sperm is placed directly into the uterus, bypassing the cervix, around the time of ovulation. This shortens the sperm’s journey to the fallopian tubes and enables more sperm to reach the tubes by avoiding the natural filtering at the cervix. This increases the likelihood of the sperm meeting the egg and thus the chance of pregnancy.

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When should IUI be performed?

There are many reasons couples may have difficulty conceiving. IUI can be helpful in overcoming some of these:

 

Unexplained infertility

The most common use of IUI is for unexplained infertility, where no clear reason for infertility can be found. In these cases, fertility medications (taken orally or by injection) are often combined with IUI to stimulate the ovaries to mature multiple eggs simultaneously, increasing the chance of sperm meeting an egg.

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Cervical stenosis or abnormalities

If the cervix is too narrow for sperm to pass from the vagina into the uterus, IUI may help achieve pregnancy. Cervical narrowing is more commonly seen in women who have undergone cervical procedures (such as cryosurgery, conization, or LEEP).

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Problems with sperm delivery

IUI may be the first-choice treatment if the male partner has difficulty with ejaculation due to erectile dysfunction, prior surgeries, or medical conditions like diabetes. It is also used in cases of retrograde ejaculation, where sperm flows backward into the bladder instead of out through the urethra during orgasm.

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Lack of ovulation (anovulation)

Even women who do not ovulate regularly can sometimes conceive with regular intercourse. However, using fertility treatments to induce ovulation (ovulation induction, or OI) and combining this with IUI can improve the timing of sperm-egg contact and increase chances of pregnancy.

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Fertility preservation

In men facing procedures like vasectomy, testicular surgery, or cancer treatments (radiation/chemotherapy), sperm can be collected and frozen (cryopreservation) beforehand. These frozen samples can later be thawed and used in IUI when pregnancy is desired.

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How is sperm collected?

Sperm for IUI can be collected in several ways. The most common method is for the male partner to ejaculate into a sterile glass or plastic container via masturbation. Sperm may also be collected during intercourse using a special condom provided by the doctor. In cases of retrograde ejaculation, sperm can be retrieved from the man’s urine in a lab.

 

How is IUI performed?

The sperm sample is “washed” in the lab to concentrate it and remove the seminal fluid, which can cause severe cramps in women. This process takes about two hours. IUI must be timed close to ovulation. The procedure itself is relatively simple and takes just a few minutes once the sample is ready.

The woman lies on an examination table. A fertility specialist inserts a speculum into the vagina to visualize the cervix. A catheter is inserted through the cervix into the uterus, and the washed sperm is slowly injected.

This procedure is usually painless, but some women may experience mild cramping or spotting for a day or two afterward.

 

Does IUI work?

Success rates vary depending on the underlying cause of infertility. IUI is most effective in couples with unexplained infertility, cervical issues, or ejaculation problems. For instance, in cases of unexplained infertility, using ovulation-inducing drugs with IUI can double the pregnancy rate compared to no treatment.

However, IUI is less effective for men with very low sperm count or severe sperm abnormalities. It is also less effective in women with severe fallopian tube disease, moderate to severe endometriosis, or a history of pelvic infections. In such cases, treatments like IVF/ICSI may be better options.

Are there any risks associated with IUI?

If the woman is taking fertility medications to increase the number of eggs, there is a slightly increased chance of twins or triplets. IUI does not increase the risk of birth defects. The overall risk of birth defects is about 2% to 4% whether pregnancy is achieved naturally or through IUI. The risk of developing an infection after IUI is low.