IUI - Intrauterine Insemination
What is IUI?
IUI (sometimes referred to as artificial insemination) stands for intrauterine insemination. It is a fertility treatment that places sperm directly into the uterus.
Who needs IUI?
The IUI procedure can be used to overcome a variety of mild fertility problems, many of them on the male side.
Male infertility indications for IUI are:
- Low sperm count, in which there are not enough sperm for a decent chance of natural fertilization. The sperm have a lower chance of fertilizing the egg, simply because there aren't as many sperm.
- Low sperm motility, in which sperm have suboptimal ability to swim up to reach and fertilize the egg.
- Cervical factor infertility, in which cervical mucus negatively impacts sperm motility.
- Sexual dysfunction.
IUI is also used when patients use donor sperm, a process called donor insemination. CHR works with reputable sperm banks where patients can select and procure semen samples for IUI. Donor insemination becomes necessary when the male does not produce sperm of a sufficient quantity and quality, and semen extraction procedures like Testicular Sperm Extraction (TESE) fail. Donor insemination is also routinely used for single women who want to conceive on their own.
In cases of so-called "unexplained" infertility, some physicians employ IUI. However, since CHR does not believe that "unexplained infertility" really exists – we believe that in "unexplained infertility" cases, something important has been overlooked during the diagnostic process – we focus on identifying the root cause(s) and devising a treatment plan that specifically target the root cause(s).
How does the IUI procedure work?
Ovulation induction before intrauterine (artificial) insemination
IUI is usually combined with ovulation induction, a process in which a woman's ovaries are mildly stimulated to produce more than one mature egg. Having more than one mature egg means that the sperm have a better chance of "meeting" an egg and fertilizing it, improving the probability of success.
During ovulation induction, in the weeks leading up to IUI the female patient takes medication to make her ovulate. This can be clomiphene citrate (Clomid), taken in oral tablet form, or a group of medications called gonadotropins, which are injected. Clomid is the mildest form of ovarian stimulant, though it can have some unpleasant side effects. At CHR, all patients undergoing ovulation induction are monitored: the growth of ovarian follicles (fluid-filled sacs that contain eggs) is monitored by vaginal ultrasound, and hormone levels are checked by blood tests.
The intrauterine (artificial) insemination process
When the ovaries have a good number of mature eggs, a hormonal injection (hCG) is used to trigger ovulation (release of the eggs from the ovaries). This injection determines when the patient ovulates. Inseminations are timed accordingly, and the male partner produces the sperm, which are washed and prepared in the lab. At CHR, we inseminate twice every month in most cases, once just before and again just after ovulation, on consecutive days.
By placing sperm directly into the uterus via IUI, the greatest barrier--the mucus in the cervix--is bypassed, and sperm do not have as far to travel to meet the egg in the fallopian tube. Therefore, more sperm reach the egg, creating a better chance of fertilization.
How Do IUI Success Rates Compare to IVF Success Rates?
What are the risks of IUI?
The main risk of IUI is the risk of multiple gestations, especially of high-order multiples (triplets or more). This is an inherent risk that is extremely difficult to avoid because physicians have limited control over the number of eggs released at the time of ovulation, and the number of eggs that are fertilized by the semen from the IUI. Physicians try to strike the right balance between good pregnancy chances and a low risk for multiple gestations, but even in best of hands, high-order multiples will happen.
Indeed, some years ago physicians from CHR published a classic paper on the subject in the prestigious New England Journal of Medicine (Gleicher N et al., Reducing the risk of high-order multiple pregnancy after ovarian stimulation with gonadotropins. N Engl J Med 2000;343:2-7). This study demonstrated that, even with best precautions, in IUI there is simply no way to control the number of eggs that are available for sperm to fertilize, and the number of eggs that actually do get fertilized. CHR researchers concluded in the paper that a high level of control over the multiple birth risk is only possible through in vitro fertilization (IVF). As a consequence of this paper, the practice of infertility has changed significantly, with the number of IUI cycles declining and number of IVF cycles increasing worldwide.
Fertility practice has come to try to avoid multiple births, especially high-order multiples, because they carry elevated risks, especially of premature delivery. The goal of good infertility treatment is, of course, not only to achieve pregnancy but to achieve pregnancy responsibly, and with as low a risk as possible to mother and newborn children.
Norbert Gleicher, MD, leads CHR’s clinical and research efforts as Medical Director and Chief Scientist. A world-renowned specialist in reproductive endocrinology, Dr. Gleicher has published hundreds of peer-reviewed papers and lectured globally while keeping an active clinical career focused on ovarian aging, immunological issues and other difficult cases of infertility.
Last Updated: October 8, 2018