Evaluating pregnancy rates and risk of twins with ovarian stimulation

This analysis compared gonadotropin hormone treatment versus oral drugs for use with intrauterine insemination (IUI). This study found that hormone treatment increased pregnancy rates but also had a higher risk of twins.

Ovarian stimulation with IUI is a standard initial treatment for infertility. Ovarian stimulation uses hormones to help the ovaries make more eggs. However, it also increases the risk of a multiple pregnancy (twins or triplets). Multiple pregnancies are more likely to have complications.

Gonadotropin hormones (GH) or oral medications can be used to stimulate the ovaries. These include drugs such as letrozole (Femara) and clomiphene citrate (Clomid). These medications help the body produce gonadotropin hormones. Studies suggest that GH results in more births and multiple pregnancies compared to oral medications. It is unclear if GH is better for routine use with IUI than oral medications.

This study looked at 8 studies that included 2,989 female patients. Patients received either GH or oral drugs (such as letrozole or clomiphene citrate) to stimulate their ovaries for IUI. All male partners had normal or mildly impaired sperm function.

Overall, patients treated with GH were 4% more likely to become pregnant compared to those treated with oral drugs. GH increased the chances of a single IUI cycle resulting in birth by 38% compared to oral drugs. There was no difference in the miscarriage rate with GH compared to oral drugs.

In a separate analysis, the authors looked at whether canceling the IUI procedure affected pregnancy rates. With a cancellation policy in place, GH did not increase pregnancy rates compared to oral drugs. Without a policy, GH increased the rates of overall pregnancy (by 11%) and multiple pregnancy (by 13%). 

The authors also looked at looked at the effects of high doses of GH. High doses of GH increased the chances of pregnancy by 9%. The risk of multiple pregnancy also increased by 19%.

This study found that GH treatment increased pregnancy rates and the risk of twins. The authors suggest that GH may not be recommended for all patients with infertility who wish to undergo IUI.

There were differences between the studies analyzed here. This makes it difficult to compare them. GH treatment increases the risk of multiple pregnancies if an IUI cancellation policy is not in place.

Talk to your doctor about your treatment options and whether gonadotropins are right for you.