Intrauterine insemination (often abbreviated “IUI”) is a fertility treatment whereby sperm cells are isolated from an ejaculate and placed inside the upper area of the uterus (womb). The rationale here is that a majority of sperm ejaculated or deposited into the vagina never come in close proximity to an egg (it is estimated that maybe only a few 100 sperm are successful in their journey from the vagina to the fallopian tube) and that placing them closer to where they normally fertilize the egg (2/3 the way down the fallopian tube) will help boost pregnancy chances. Indications for IUIs include couples with male factor or unexplained infertility, same sex couples and single females desiring pregnancy.
Although there are many factors affecting treatment success, IUI can generally be expected to yield a pregnancy rate of about 15% per month. Considering that peak fertility in young couples trying to conceive at home through timed intercourse is around 20-25% per month, IUI for those needing assistance is a reasonable treatment approach. However, in an effort to boost IUI success rates, different strategies have been applied. One such approach is to perform two IUIs per month (aka “double IUI”). The idea here is that the overall concentration of sperm in the fallopian tube would increase and the window of opportunity to fertilize the egg would widen.
A new study published this month seems to put the idea of double IUI to rest. A large, private fertility center studied almost 4000 donor IUI cycles over a 3 year period and found no advantage to a double IUI. This was true whether the cycles were natural (1 egg produced) or medicated (potentially yielding multiple eggs in a single month). Both single IUI and double IUI yielded pregnancy rates hovering at around 15%.
For the patient a single IUI holds the advantage of one less office visit, one less procedure and a significant cost savings.
In the case of IUI, two are not better than one.