Intrauterine insemination (IUI), also known as artificial insemination, is a treatment that places sperm directly inside the uterus with a catheter.

What is IUI?

Intrauterine insemination (IUI), also known as artificial insemination, is a treatment that places sperm directly inside the uterus with a catheter. By placing a concentration of sperm closer to the eggs, IUI can increase the chances for fertilization for some patients.


Fertilization is the union of an egg with a sperm. During natural fertilization, this process typically occurs in the fallopian tube. Once inside the fallopian tube, many sperm must attach to the outside of the egg. Once connected, a single sperm pushes through the outer layer of the egg to the inside (cytoplasm). A fertilized egg is also called a zygote.


Embryo Transfer during IVF at Lane Fertility Institute

How does IUI improve fertility success for some patients?

IUI can overcome some of the challenges sperm faces when trying to reach an egg. When ejaculated sperm are released during intercourse, the sperm have to swim through two barriers to reach an egg: the vagina and the cervix. Surprisingly, 90% of sperm never gets out of the vagina. Of that 10% that do, only 10% of those will make it through the cervix (1% of the total sperm ejaculated).

IUI improves the chances of sperm reaching and fertilizing an egg. The washing and concentration of sperm and the insertion of the sperm directly into the uterus increase the odds that healthy sperm will be able to swim up the fallopian tube to reach, attach to an egg, and fertilize it.

IUI is often one of the initial treatments tried for unexplained infertility or male factor infertility.

Who is a good candidate?

Intrauterine insemination is used most often with patients who may have one or more of the following situations:

  • Male factor infertility. One of the first steps in assessing infertility is an analysis of the male partner’s sperm. Semen analysis may indicate above-average sperm abnormalities, including sperm size and shape (morphology), weak movement (motility) of sperm, or low numbers of sperm (concentration). IUI can overcome some of these problems. Sperm preparation for IUI helps separate highly motile, normal sperm from those of lower quality.
  • Donor sperm is being used by the couple or individual. IUI is often used for patients who need to get pregnant using donor sperm. In this case, frozen donor sperm specimens are obtained from a certified lab before the IUI procedure.
  • Unexplained infertility. When combined with ovarian stimulation medications, IUI can be a solution for some cases of unexplained infertility.
  • Semen allergy. Although rare, an allergy to proteins in semen can cause infertility. If sensitivity to the proteins is severe, ejaculation into the vagina causes redness and burning where the semen contacts the skin. IUI can be an effective solution because many of the proteins in semen are removed before sperm is inserted.

Evaluating IUI success rates:

IUI pregnancy rates peak at ~16%, with total motile counts (TMC) of more than 9 million sperm per specimen. These rates decreased to less than 5% in patients with TMC of less than 2 million. In addition, the age of the egg significantly impacts pregnancy rates with

One of the success variables with IUI is age. IUI is most successful with women under the age of 41.

To assess the chances for fertility success, the female patient has a fertility evaluation which includes a medical history and an ultrasound to examine the health of the woman’s fallopian tubes.

A semen analysis of the male partner or sperm donor is also done. The semen sample needs to be normal or only slightly abnormal for IUI to be recommended.

What steps are involved?

An IUI procedure is performed at the time of a woman’s peak ovulation (when a mature egg is released from an ovary).

Depending on the determined cause of infertility, IUI is coordinated with a woman’s normal cycle with or without added fertility medications. For optimized effectiveness, a woman will often take ovarian stimulation medications such as follicle-stimulating hormone (FSH) or human chorionic gonadotropin (HCG) to increase her egg (ova) production.

How does a woman monitor her ovulation for an IUI treatment?

Because the timing of IUI is so critical, a woman must monitor herself for signs of impending ovulation. An at-home urine ovulation predictor kit can be used that detects when the body produces a surge or release of luteinizing hormone (LH).

A transvaginal ultrasound may also be done to ensure optimal timing for IUI. This allows the provider to see the ovaries and egg growth.

How is male sperm prepared for an IUI treatment?

Sperm from either a partner or sperm donor is collected, washed, and concentrated. This “washing” takes between 30 and 60 minutes and separates the sperm from the other parts of the semen, concentrating the sperm into a small volume.

Washing also strips the sperm of certain proteins that can sometimes irritate a woman’s uterine tissue and reduce the success rate of a treatment.

Finally, washing improves sperm motility (a sperm’s ability to swim to an egg).

How is sperm collected from the male?

Sperm is typically collected by ejaculation into a sterile container in a doctor’s office or at home. The male providing the sample will follow these guidelines:

  • No sex or masturbation for 2-5 days before providing a semen specimen
  • Avoidance of caffeine, alcohol, and certain medications prior to providing a sample
  • The use of a sterile container provided by a fertility clinic with careful labeling as to the time of ejaculation, name, date of birth
artificial insemination
sperm insertion

What to expect during and after an IUI treatment

The IUI procedure is a short process. The entire treatment typically takes only about 20 minutes. A fertility doctor or a specially trained nurse performs the procedure.

The IUI procedure begins with the patient lying on an exam table. A speculum is inserted into the vagina, similar to what one experiences during a Pap test.

artificial insemination

During the procedure:

  • The cervix is gently cleaned
  • A vial containing the sample of healthy sperm is attached to the end of a long, thin, flexible tube (a catheter)
  • The catheter is inserted into the vagina cavity, through the cervical opening, and into the uterus cavity
  • The sperm sample is released through the tube into the uterus

After the injection of sperm is completed, the patient will spend several minutes resting on the exam table in order to maximize the outcome of the IUI process. After the procedure, light spotting may be experienced for a day or two.

Pregnancy Test

About two weeks after the procedure, a pregnancy test should be taken to see if a pregnancy has occurred. Testing prior to two weeks could result in a false-negative or a false-positive.

If a pregnancy has not occurred, IUI can be tried additional times before another fertility treatment is recommended. Often, IUI is tried for several months to maximize the likelihood of success.

What treatments are considered if IUI is not successful.

Typically if a woman is not pregnant after several IUI attempts, the possible reasons could be:

  • Eggs and sperm are not finding each other
  • Eggs and sperm are not interacting appropriately to achieve a fertilized embryo
  • The fertilized embryo is not able to make an implantation

If IUI does not prove to be successful, other treatment options such as IVF and INVOcell can be considered with your fertility specialist.


The experienced team at LFI has helped many patients achieve pregnancy with IUI. Contact Lane Fertility for a consultation to discuss IUI, today.