Intrauterine insemination (IUI) is one of the simpler treatments for infertility and the starting point for many individuals and couples trying to conceive. IUI is frequently the first line of treatment in couples with unexplained infertility, mild male factor infertility, a cervical factor, and irregular or absent ovulation. A physician may also recommend IUI in cases where a woman or couple needs donor sperm. Before you and your doctor make the decision about whether or not IUI is right for you, you will undergo standard infertility testing.
What to Expect
Intrauterine insemination is the process whereby your physician will place a concentrated specimen of sperm in your uterus. For this procedure, he or she will insert a speculum into your vagina in order to better visualize your cervix. He or she will then pass a soft, thin catheter through the cervix opening and into the uterus. The clinician will introduce the washed sperm into the uterus through this catheter. The procedure is done in our office and takes 1 to 2 minutes. It is not painful and does not require anesthesia. You can return to normal daily activities immediately after an IUI.
Our specialized team of andrologists prepare each sperm sample with a procedure commonly known as "sperm washing" in our andrology laboratory. Sperm washing involves placing the sperm sample in a test tube and then a centrifuge, which results in the sperm collecting in a "pellet" at the bottom of the test tube. The andrologist removes the seminal fluid and places the fluid (media) above the sperm. The most active sperm will then swim up into the media. The final sample consists of the most active sperm concentrated in a small volume of media. A single IUI is usually performed when a patient is using fresh sperm. If a patient is using a frozen sperm sample, the clinician can likely perform one or two IUIs.
Timing the Insemination
Our physicians generally perform IUIs 1 and a 1/2 days after the trigger injection, which sets ovulation in motion. The exact timing of insemination is not critical to the exact time of ovulation. Both the sperm and the egg remain viable in the female genital tract for many hours, so the physician may time the insemination within a window of several hours around the time of ovulation. Following the IUI, you will take daily supplemental progesterone—usually in the form of a capsule inserted into your vagina twice a day—to support the endometrial lining of the uterus and implantation of the embryo.
IUI Success Rates by Age
For couples that have no difficulty achieving a pregnancy, the natural chance of pregnancy per month of ovulation depends on the age of the woman. For women up to the early 30s, the natural pregnancy rate is about 20 to 25 percent per cycle. This drops off significantly through the mid and later 30s; by the early 40s, the chance of pregnancy is about 5% per cycle. This age related decrease is primarily due to a decline in the quality of the eggs within the ovaries.
For couples having difficulty achieving a pregnancy, unless both tubes are completely blocked, there is no sperm, or the woman never ovulates, their chance of achieving a pregnancy is not zero, it is just lower than average (to a greater or lesser degree). Ovulation induction or superovulation with IUI helps patients to achieve pregnancy rates closer to the natural per cycle chance of pregnancy for women in their age group who do not have infertility (see fig 1).
Figure 1. Pregnancy rate per cycle following OI or superovulation with intrauterine insemination (IUI) according to female age.
As the chance of pregnancy per treatment cycle is modest, it may take more than one cycle of treatment in order to achieve a pregnancy. However, if it has taken more than 3-4 cycles of treatment and there has not been a pregnancy, it may be advisable to move to more aggressive treatments such as IVF.
IUI Pregnancy Rates by Diagnosis
In addition to age, a couple’s prognosis for success with OI/IUI or superovulation/IUI depends on their diagnosis (see figs 2 and 3). This treatment is most successful in couples where the primary cause for infertility is ovulatory dysfunction or failure of regular ovulation such as with polycystic ovary syndrome (PCOS). In these cases, the treatment comes closest to restoring the natural per cycle pregnancy rate.
Superovulation/IUI is also quite successful for the treatment of mild male factor or unexplained infertility, although the success rates are slightly lower than for those couples where ovulatory dysfunction is the only problem.
Superovulation/IUI is less successful if the cause of infertility involves diseased fallopian tubes, endometriosis or decreased egg quality. This is due to a couple of reasons. First, superovulation does nothing to improve the quality of the eggs within the ovaries. Even with IVF, the chances for pregnancy with poor egg quality are quite low. Next, if the fallopian tubes are damaged, there will be a decreased chance for fertilization and early embryo growth to occur properly. The fallopian tubes are where fertilization takes place and where the embryo grows for its first few days before making its way to the uterine cavity for implantation. If one of the fallopian tubes is blocked, it may be due to inherent disease involving both fallopian tubes; even if the other fallopian tube is open, it may not be able to provide the appropriate nurturing environment for fertilization and early embryo growth to take place. As with advanced age, it may be advisable to move to IVF earlier in the treatment timeline with these diagnoses.
Figure 2. Pregnancy rates following IUI according to age and diagnosis (red = ovulation disorders / PCO, gold = unexplained and mild male factor, and blue = diminished ovarian reserve, uterine, and tubal factors).
(% per cycle)
|Miscarriage||Live Birth / Ongoing |
(% per cycle)
|Unexplained||3690||546 (14.8%)||89||458 (12.4%)|
|Ovulation Disorder / PCO||2238||448 (20%)||74||374 (16.7%)|
|Male Factor||1154||173 (15%)||27||146 (12.6%)|
|Endometriosis||418||38 (9%)||3||35 (8.4%)|
|Tubal Facor||234||27 (11.5%)||3||24 (10.3%)|
|Uterine Factor||137||18 (13.1%)||4||14 (10.2%)|
|Dimished Ovarian Reserve||125||14 (11.2%)||3||11 (8.8%)|
Figure 3. IUI treatment outcomes according to diagnosis, age<38 years, 2003-2006
IUI and Multiple Pregnancies
A major concern for couples undergoing any fertility treatment is the risk of multiple pregnancy. Because of our close attention to patients undergoing stimulation, we are able to keep the multiple pregnancy rates quite low for our patients (see fig. 4). For those couples undergoing OI/IUI with clomiphene alone, the risk of twins is about 11% and we have had 2 triplet pregnancy in the last 5 years. For those couples treated with superovulation/IUI, the risk of twins is about 16% with the risk of high order multiple (triplets and higher) <3.5%. The risk of multiples declines with a woman’s advancing age (see fig. 5).
Figure 4. Multiple pregnancy rates following IUI according to stimulation protocol.
Figure 5. Multiple pregnancy rates following IUI by patient age.
Are there different types of IUI cycles?
There are different types of IUI cycles based on your individual diagnosis and your response to treatment:
Nonmedicated cycle with IUI: Also known as natural cycle IUI, a non-medicated cycle with IUI is often used by single women or same-sex female couples who are not directly experiencing infertility, but rather a lack of sperm. This treatment involves tracking the development of the egg that is naturally recruited during a menstrual cycle and then introducing the donated sperm. You will come into the office for two to five monitoring appointments to track egg development and cycle timing.
Ovulation induction with IUI: The goal with ovulation induction is to recruit and develop a single egg during the stimulation phase. At the time of ovulation, insemination occurs, placing the sperm directly into the uterus. IUI puts the sperm closer to the egg than possible with intercourse alone. You will come into the office for four to eight monitoring appointments to track egg development and cycle timing.
Injectable medication cycle with IUI: If pregnancy doesn't result from ovulation induction with IUI, the next step is to use injectable medications. These medications stimulate the ovaries to produce two to four eggs; when combined with IUI, you have an increased possibility of conception. Essentially, the sperm is given more targets to hit. You will come into the office for four to eight monitoring appointments to track egg development and cycle timing.