Intrauterine Insemination (IUI) Success Rates
IUI Pregnancy 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 – 25% 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. Watch our IUI Program & Low-Tech Treatments Webcast -->
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). Learn more about our IUI Program -->
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.
Because the chance of pregnancy with ovulation induction or superovulation with IUI for those women over the age of 40 is low, it may be advisable to move to IVF earlier in the treatment timeline. Check to see if SGF participates with your insurance -->
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). Learn more about ovulatory disorder -->
(% per cycle)
(% 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.