Controlled Ovarian Stimulation (COS) with Gonadotropins
Gonadotropins are injectable medications that result in the growth of multiple follicles in the ovaries. Controlled Ovarian Stimulation (COS) with Gonadotropins could be called “not so controlled ovarian stimulation with gonadotropins” as it can lead to not only a high risk of twin pregnancy, but also to high order multiple pregnancies such as triplets or quadruplets or more. Protocols to restrict the medication dose or limit the effects of the medication during treatment have failed to prevent these high-risk multiple pregnancies from occurring. Because of the multiple pregnancy risks, COS with gonadotropins is not the preferred method to induce ovulation in today’s practice. However, it can be combined in low doses with clomiphene or letrozole if these oral medications fail to achieve ovulation in some cases.