What is an IUI?

Intrauterine Insemination

An intrauterine insemination (IUI), also known as artificial insemination, is a procedure involving the injection of a sperm sample into a woman’s uterus in an attempt to achieve fertilization and a pregnancy. IUIs may help circumvent issues causing infertility, such as hormonal imbalances or cervical issues, and can also help same-sex couples achieve a pregnancy through the use of donor sperm. IUIs are less invasive and expensive than in vitro fertilization (IVF) and are often performed prior to an IVF cycle. If multiple IUIs are unsuccessful, IVF may be warranted.

IUIs are typically performed 1-3 days after ovulation occurs, during which time the egg exits the ovary and enters the Fallopian tube. The goal of an IUI is for the injected sperm to swim through the uterus and into the Fallopian tube, where it encounters the egg so fertilization can occur. If fertilization occurs, the embryo will spend the next few days moving from the Fallopian tube into the uterus, where it should implant into the uterine lining (endometrium). 

There are a few steps involved in an IUI procedure, which are outlined below:

Medications and Monitoring

Though some IUI cycles are performed without a need for any medications (unmedicated), others require the administration of medications that stimulate an egg (or more) to mature in the ovaries and control the timing of ovulation.

If needed, these medications are typically administered at the beginning of the menstrual cycle. Another medication, called a trigger medication (hCG is a common example), is often administered prior to ovulation. This medication triggers ovulation to occur, which determines when the IUI should be performed.

Monitoring is often performed via two methods leading up to an IUI:

  1. Ultrasounds of the ovaries are performed to determine if a follicle (or more) is growing. In a normal menstrual cycle, multiple follicles begin to grow, but only one ultimately grows while the others degenerate. This follicle, called the dominant follicle, contains the egg that is ovulated during that menstrual cycle. If a follicle appears to be growing during an IUI cycle, it is presumed that the egg inside of the follicle is maturing in preparation for ovulation.
  2. Blood is drawn to test hormone levels. This can help determine if the hormone levels are within normal limits and if ovulation is approaching or has approached. Ovulation predictor kits or urine tests can also be used to determine when ovulation is approaching or has occurred.

The IUI Procedure

On the day of the IUI procedure, a sperm sample is either brought to (if it’s fresh) or thawed at (if it’s frozen) the IVF clinic. At Pelex, we utilize the ZyMot device to prepare sperm samples for IUIs. This process separates the motile sperm from the immotile sperm and other debris in the semen sample. 

At the time of the IUI, the washed sperm sample is loaded into a thin, flexible catheter. The catheter is then inserted into the uterus near the Fallopian tube, and the semen sample is expelled into the uterus. The injected sperm then travel to the egg(s) in the Fallopian tube, where fertilization should occur. 

IUIs are generally not painful and do not require sedation. Some side effects may include abdominal cramping or mild pain and spotting. IUIs are routine procedures that carry very few risks.

After the IUI

The entire procedure only takes about 5-10 minutes, and the patient may be asked to lay on her back for roughly 30 minutes following the procedure. Afterward, the patient is able to leave the clinic and resume her regularly-scheduled activities (overly-strenuous activities should be avoided).

Some patients will continue to administer a medication that contains the hormone progesterone after the IUI procedure. This hormone helps to thicken the uterine lining and sustain a pregnancy. A blood pregnancy or at-home pregnancy test is typically scheduled roughly 2 weeks after the IUI has been performed to determine if embryo implantation has occurred.

If implantation does occur, routine followup tests will be ordered and the patient will continue taking progesterone (if it is a medicated cycle) until instructed to stop.

If implantation does not occur, the patient will stop taking progesterone (if she was taking it) and her period should begin a few days later.


Intrauterine insemination (IUI) - Mayo Clinic

IUI (Intrauterine Insemination): What It Is & What To Expect (clevelandclinic.org)

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