Ovarian stimulation is the second stage of IVF fertility treatment. The goal is to harvest as many mature eggs as possible from the woman’s ovaries. Harvesting many eggs maximizes the chances one of the eggs can be fertilized, implanted back into the uterus, and become a healthy baby. Because the natural female reproductive cycle is incredibly complex, ovarian stimulation is also a complicated process. An IVF cycle can be stressful, especially when you’re going through it for the first time.
When Ovarian Stimulation Is Used?
Ovarian stimulation is generally used:
- To induce ovulation in patients with ovulatory dysfunction to help them conceive.
- For egg retrieval in IVF treatments.
- To store oocytes (eggs) for future use.
How Ovarian Stimulation Works?
In a natural ovulatory cycle, natural hormonal changes dictate the maturation and release of the egg. In some women, however, this does not occur naturally and so medications are given to the patient in order to stimulate the ovarian function. This makes it possible to schedule each hormonal change, thus optimizing the quality of the oocytes that are released.
Stages Of IVF Treatment
- Ovarian stimulation
- Oocyte retrieval
- Insemination/ ICSI
- Embryo transfer
There are two types of ovarian stimulation: the long protocol and the antagonist protocol. The process of ovarian stimulation is generally started a week before the expected date of the next menstrual period in the long protocol. In the antagonist protocol, stimulation is started from the second day of the menstrual cycle. Several hormones are administered so that several matured oocytes can be retrieved at a single egg retrieval procedure.
Ovarian stimulation is achieved by gonadotropins injections that contain follicle stimulating hormone (FSH) and luteinizing hormone (LH). These stimulate the growth of multiple follicles in the ovaries. FSH injections are given for about 10 days before the patient is ready for the oocyte retrieval.
The patient is closely monitored with the help of an ultrasound, during the ovarian stimulation stage. The number of follicles present is counted and their size is measured. If sufficient follicles over 17-18 mm in diameter are found, the egg retrieval process is scheduled. A final HCG injection is given to promote the final maturation of the eggs.