Are progestins as effective as gonadotrophin releasing hormone medications for women trying to conceive?

This study compared the effectiveness and safety of progestins to gonadotrophin-releasing hormone (GnRH) medications for women trying to conceive. The results showed that progestins were as effective and safe as GRH medications and could be used as a cheaper alternative.

For women using medical assistance to conceive, an important part of treatment is the blocking of certain hormones to allow pregnancy. Luteinizing hormone (LH) is required for the release of an egg from the ovaries. However, too much LH will prevent the release of eggs.  

Progestins and GnRH medications can be used to lower the levels of LH in the body. GnRH medications have been used for many years and come as an injection. Progestins are a synthetic version of progesterone. They come as a tablet and are cheaper than GnRH medications. However, it is unclear if progestins are as safe and as effective as GnRH medications during infertility treatments.

Data from seven studies including 1548 women were analyzed. Approximately half of the women had been given progestins and the other half GnRH medications. GnRH medications were either GnRH antagonists (blockers; 3 studies) or agonists (stimulators; 4 studies).

In one study, a similar number of eggs were released following progestin (10.7 eggs) and GnRH antagonists (11.1 eggs). Another study showed that more eggs were released after progestin treatment (33) than GnRH antagonist treatment (26).

Patients who had an egg fertilized in a lab had a similar birth rate after progestin treatment (40%) and GnRH antagonist treatment (38.1%). Patients who received eggs from egg donors had a slightly lower birth rate after progestin treatment (22%) than GnRH antagonist treatment (30.7%).

The rate of miscarriage was similar after progestin treatment (24.3%) and GnRH antagonist treatment (23%). The rate of multiple pregnancies was also similar after progestin (2.9%) and GnRH antagonist treatment (2%).

Patients had a 49% higher chance of having a birth after progestin treatment than GnRH agonist. Patients were 14% more likely to become pregnant with progestin treatment than GnRH agonist treatment. A similar number of eggs were released after progestin treatment and GnRH agonist treatment.

Patients were 2.26 times more likely to have an ectopic pregnancy (outside the womb) but 23% less likely to have a miscarriage with progestin treatment than GnRH agonist. There were no differences between the number of patients with multiple pregnancies after both treatments.

The authors concluded that progestins are an effective, safe, and cheaper alternative to GnRH medications in women undergoing assisted reproduction techniques.

The studies included in this analysis were set up differently and it is difficult to compare them. Patients received other treatments as part of their care, and these were not factored into the analysis. This information should be confirmed with a large controlled clinical trial.