In a nutshell
This article gives an overview of ovarian stimulation (OS) during assisted reproductive techniques (ART).
Many couples with infertility opt to use ART. In vitro fertilization (IVF) is an ART in which eggs are collected and fertilized embryos are implanted in the uterus. The first step of IVF is to cause multiple ovarian follicles to develop using OS medications. This allows for the collection of multiple eggs. OS is the foundation of a successful IVF cycle. Some women produce few eggs in response to OS. These women are said to have a poor ovarian response (POR). It is important to review the current methods of OS and find the optimum method for each patient.
Methods & findings
Gonadotropin hormones are most commonly used for OS. Human menopausal gonadotropin (hMG; Menopur) is isolated from the purified urine of postmenopausal women. hMG is a mixture of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and human chorionic gonadotropin. Recombinant FSH (rFSH; Gonal-F) was created by splicing human genes into hamster ovarian cells. hMG and rFSH are both effective for OS and lead to similar birth rates. Recombinant LH (rLH) has also been developed. Women who are over 38 years or have POR may benefit from using both rFSH and rLH.
Mild OS is another option. Mild OS typically uses oral medications such as clomiphene citrate (Clomid) or letrozole (Femara). Both medications cause the body to release more of its own gonadotropin hormones. Low doses of gonadotropins may also be considered mild OS. Mild OS is less expensive and is gentler on the body than gonadotropin OS. Mild OS is closer to a normal menstrual cycle. It may also make the uterine lining easier for the embryo to implant in. For women with POR, mild OS leads to similar pregnancy rates as gonadotropin OS.
In a natural menstrual cycle, a sharp rise in LH triggers ovulation. During IVF, this LH spike must be prevented from happening too early. Gonadotropin-releasing hormone (GnRH) prompts the release of LH. GnRH agonist treatment such as buserelin (Suprefact) acts like a constant GnRH signal, which causes the pituitary gland to ignore GnRH. In contrast, GnRH antagonists such as cetrorelix (Cetrotide) directly block the pituitary gland from responding to GnRH. Both the agonist and antagonist are effective in preventing an LH surge. GnRH antagonist has a lower risk of ovarian hyperstimulation syndrome (OHSS) and takes a shorter amount of time. OHSS is an exaggeration of OS that leads to swelling and pain in the ovaries.
Recent studies have investigated using progestins (synthetic progesterone) to block LH during IVF, as it is already used in the progestin contraceptive pill. Early results have found progestins result in similar IVF pregnancy rates to other methods.
The bottom line
This study reviewed OS methods in women seeking IVF.
These are general guidelines. Your doctor will work with you to decide the best treatment based on your health history.
Published By :
May 24, 2020