Which patients can benefit from intrauterine insemination?

This study looked at how a couple’s health background and treatment affect intrauterine insemination (IUI) outcomes. It found that semen quality, female age, and type of fertility medications influence results.

IUI is often the first treatment for couples with infertility that does not have a clear cause. This treatment involves injecting semen into the uterus. IUI can be done during a natural menstrual cycle prior to expected ovulation. The procedure is timed by tracking the cycle using ultrasound or other methods. Alternately, IUI is often combined with ovarian stimulation (OS), which uses medications to stimulate ovulation.

Some studies have found that men with low sperm quality have poor IUI results. However, it is not clear what is the minimum sperm concentration at which a couple will benefit from IUI. It is also not clear how sperm quality relates to other factors, such as the woman’s age.

This study included 1117 female patients undergoing 2912 cycles of IUI. A sample of the sperm used for the IUI was analyzed. Some patients used OS with gonadotropin hormones, which stimulate the ovaries. Most cycles used OS with oral medications such as clomiphene (Clomid) or letrozole (Femara). Oral OS causes the brain to release its own gonadotropins. Few patients used natural cycle IUI.

A cycle using oral OS had 50% the odds of birth of one using gonadotropin hormones. Sperm motility (the percentage of sperm which move normally) was also related to outcomes. A 10% increase in motility increased the odds of birth by 20%. It was estimated that women under age 35 can use IUI with oral OS if sperm motility is at least 49%.

Female patients age 35 to 37 years old were almost as likely to have a live birth as those younger than 35 (9.9% vs. 10.5%). IUI with oral OS was considered suitable for these patients if sperm motility is at least 56%. IUI with gonadotropins was also considered suitable.

There was a lower birth rate for women 38 to 40 years old (5.1%) and 40 to 42 years old (5.2%). For these patients, it was estimated that IUI with oral OS is not a suitable treatment. IUI with gonadotropins can be used if sperm motility is at least 60%.

This study found that sperm motility and female age both influence live birth after IUI. The authors suggested that couples with higher female age or lower sperm motility should use gonadotropins, which have higher success than oral OS.

Gonadotropins also increase multiple pregnancies (twins or triplets), which raises the risks of pregnancy.

Talk to your doctor about whether IUI is suitable based on your health history, and which types of OS are appropriate. In vitro fertilization may be an option for couples who are not good candidates for IUI.