Sperm Washing and IUI

Intrauterine insemination, or IUI, is a relatively simple infertility treatment for couples with specific fertility problems.  IUI is the last step most doctors recommend before moving on to in vitro fertilization, because it’s a relatively painless procedure.  The process happens in two steps.  First, a semen sample collected from the male donor goes through a process called sperm washing.  Then the “washed” sperm are slowly inserted into the uterus.

It might seem odd that something as natural as sperm might need to be washed before they are introduced to a woman’s uterus – it’s not a step that most people take during intercourse.  However, ironically enough, semen is a harsh environment for sperm and fairly toxic to a female.  Sperm will die 2 to 8 hours after being combined with the fluids that form semen, and have a hard time moving in it as well.  When injected into a woman’s uterus, a volume of semen larger than a half of a milliliter will make the uterus cramp violently; if introduced anywhere else in the body it can make a woman fairly ill.

So how does anyone get pregnant if semen is such rough stuff?  The answer is cervical mucous.  When sperm reach the cervix, the opening between the vagina and the uterus, they find a thick layer of mucous, which is a much better environment.  As they move through, they are slightly altered chemically, which allows them to swim through the uterus and to the fallopian tubes.  Without passing through this mucous, sperm in semen alone cannot fertilize an egg.  In IUI, a large volume of concentrated sperm are injected directly into the uterus, bypassing the cervical mucous.  The sperm need to be washed with a nutrient rich broth, similar to what is used in IVF, in order to make them acceptable to the uterus and ready for fertilization.

The process of sperm washing actually includes two steps: the sperm washing, and the sperm sorting.  Sperm are separated from the ejaculatory fluids with the nutrient rich broth mentioned before, which is the washing step.  The cleansed sperm are then put into a test tube that contains different densities of fluids separated into layers (think separated salad dressing in test tube), and put into a centrifuge.  This spins the cells, which usually results in all the solids floating to the surface.  Remember sperm, though, are designed to swim.  For some reason when the centrifuge starts spinning sperm feel the urge to move, and they start swimming down.  It’s difficult for them to move through the different layers, however, so as a result only the strongest, most high-powered, super-active sperm make it through to the bottom.  After the centrifuge stops you have a concentrated sample of “super” sperm at the bottom of the tube, and their less motile companions are left at the top.  The concentrated sperm solution is removed from the test tube and injected into the uterus while the sperm are still in their highly activated state.

The insemination process is pretty simple.  A thin tube is inserted through the vagina and cervix and into the uterus.  The concentrated sperm sample is introduced slowly to avoid excess irritation to the uterus.  While some bleeding and cramping may occur, it should only be slight.  Many women prefer to lie down and rest after IUI, but it is not necessary.  By the time you leave the doctor’s office the sperm will have made their way to the fallopian tubes, where they will encounter and hopefully fertilize the egg.

When combined with ovarian stimulation, success rates with IUI vary between 12 and 20 percent per cycle.  This success rate is similar to results with ovarian stimulation and good old-fashioned intercourse, so IUI may not be a necessary choice for many couples (and isn’t as much fun).  But there are conditions that make IUI necessary:

• surgery that could have damaged or destroyed your cervical mucous like loop electrosurgical excision procedure  loop electrosurgical excision procedure (LEEP) or cryotherapy
• taking clomiphene citrate (Serophene or Clomid), which can damage cervical mucous
• using frozen sperm
• if there is a negative interaction between your cervical mucous and your partner’s sperm
• if your partner has retrograde ejaculation

IUI can be a simple solution to infertility for some couples.   Talk to your doctor about your specific conditions to see if you are a candidate.  Most clinics do between three and twelve cycles of IUI before moving on to IVF, although many doctors believe that you should do between three and six before trying the next step.  IUI can be less expensive than IVF, but not if you have to repeat the procedure twelve times.  A special note – be sure you and your partner have identification, such as a driver’s license, with you during all phases of IUI.  Fertility clinics have to be careful to avoid mistakes with samples and identities, and you should be wary of any clinic that isn’t.