Intrauterine insemination (IUI), also know as artificial insemination, is a procedure that places the sperm directly into the uterus. This is done by placing a long flexible catheter through the cervix and gently expelling the sperm. Before the IUI, the semen sample is collected by masturbation. Because of its alkaline pH, the seminal fluid can irritate the uterus, so it’s washed before insemination by spinning it in a centrifuge. Eggs are not retrieved for an IUI; fertilization and embryo development happen inside the body.

The IUI procedure is timed to coordinate with ovulation, so you may be asked to monitor your cycle with home ovulation predictor kits. When you see a positive surge in luteinizing hormone (the hormone that triggers ovulation), you call the clinic and make an appointment for your insemination the next day. Intercourse (and orgasm!) is encouraged following IUI to get the maximum amount of sperm to the egg. Check first with your doctor to make sure there was no bleeding during the IUI, which is very rare.

When is IUI Used?

IUI can be used only if the fallopian tubes are open and you ovulate normally. IUI has shown to be helpful in some cases of low sperm counts as the sample is centrifuged before insemination and the sperm are concentrated into a small volume of fluid. This allows more sperm to be introduced into the uterus than would happen following intercourse. IUI is also a good way to circumvent the cervical mucus, which may be hostile to sperm and prevent it from swimming through the cervix.

Success rates of IUI vary considerably and are based on the number of follicles present, the sperm count, and any other underlying factors preventing you from getting pregnant.

Natural IUI Cycle

A natural cycle IUI is usually recommended for women using donor sperm and who have no known fertility problems. The success rates for natural IUI cycles are not much higher than natural conception for people with unexplained infertility. The overall success rate per cycle is around 10%. The cost is several hundred dollars. Depending on your age and diagnosis, most doctors would recommend doing no more than three or four cycles of natural IUI before moving on to medicated IUI or IVF.

Medicated IUI Cycle

A medicated IUI cycle follows the same basic principles as a natural cycle IUI. Both involve washing and concentrating the sperm and placing the sperm directly into the uterus. With a medicated IUI cycle, you take drugs to promote follicular development and ovulation.

Success Rates of a Medicated IUI Cycle

The success of medicated IUI is approximately 20% pregnancy rate per cycle, which is slightly higher than natural cycle IUIs. The downside is the increased risk of a multiple pregnancy, especially when using injectable fertility drugs. For that reason, it’s important to have regular ultrasound monitoring of the ovaries leading up to the insemination. If many follicles develop, you may be advised to cancel the cycle and use a lower dose of drugs next time. Alternatively, an IUI cycle can be converted into an IVF cycle if there is an unexpectedly high response.

IUI with Clomid

One drug regularly used in medicated IUI cycles is Clomid, also known as clomiphene citrate. Clomid works on the brain and promotes the production of follicle stimulating hormone (FSH). This hormone stimulates the growth of follicles in the ovary and is a first line of treatment to induce ovulation. The use of Clomid carries a 5% chance of twins and a rare chance of triplets. Because Clomid can change the cervical mucus and make it difficult for the sperm to swim into the uterus and fallopian tubes, it’s often recommended that Clomid be used in conjunction with intrauterine insemination, rather than intercourse, to maximize the chance of pregnancy. Clomid is relatively inexpensive, costing only a few dollars. However, a Clomid IUI cycle could incur additional expense because of extra ultrasound monitoring and blood testing.

Letrozole (brand name, Femara) has similar effects to Clomid and similar success rates. It’s possible that patients who don’t respond well to Clomid or have intolerable side effects may do better using letrozole.

If Clomid or Femara IUI is not successful, you may be advised to advance to the next level of treatment. This could be IUI with injectable fertility drugs, or it could be IVF. It’s not advised to do more than six Clomid IUI cycles.

IUI with Gondatrophins

Injectable gonadotrophins are the same drugs used for IVF to produce many eggs at once. For an IUI cycle, the dose of gonadotrophins is much lower than in an IVF cycle, with the intention of developing only two or three follicles before insemination. Because women respond differently to these injectable medications, the doctor follows the development of the follicles with ultrasound and possibly blood tests. It’s important not to inseminate or have intercourse if you are at risk of a high-order multiple pregnancy (three or more mature follicles). Based on your age and diagnosis, the doctor assesses the risks of this happening, versus the chance of achieving a pregnancy, and proceeds accordingly. The cost of a gonadotrophin IUI cycle can be around $2,500 per cycle.