Preparing for ovarian stimulation

Women undergoing assisted  reproduction treatments, either artificial insemination, IVF or ICSI, will need to take some medication that stimulates the ovarian cycle.

This stimulation is necessary for two main reasons:

  • To know the exact stage of the woman’s menstrual cycle in each moment.
  • To stimulate the ovarian production so more than one oocyte is matured in order for the chances of pregnancy to be higher.

Numbers of oocytes retrieved

There are several stages in the hormonal treatment. Initially, contraceptives to control the menstrual cycle may be prescribed and, once the last period is finished, the next stages of the process can begin.

Oocyte maturation

The first stage involves the application of hormones that stimulate the maturation of more than one follicle in the ovary so more oocytes can be obtained.

A hormone is administered through a subcutaneous injection. This can be done at home and by the woman herself. The hormone should be injected at the same time evey day. This first phase lasts between 8 and 10 days. Depending on the reaction of the body to the hormones, on the patient’s age, on the previous cycles of stimulation, on the time of infertility, etc, a different drug and a different dose are indicated. The gynecologist always personalizes the treatment.

Medical check-up

From the 4th day after the start of the injections on a medical monitoring to check how the ovary responds to medication is done. This medical check-up is done every day or every other day so the hormonal dose can be correctly adjusted.

A transvaginal ultrasound allows the number of developed follicles in each ovary to be controlled and their sizes to be evaluated. The diameter of the follicles determine the time when the follicular puncture must be performed. Blood tests able to check the levels of estradiol (E2), which is the hormone responsible for supporting the follicular growth, are also needed.

Transvaginal ultrasound


Once the diameter of the follicles reaches approximately 18 mm and the estradiol levels are appropriate, another hormone, that will trigger the ovulation, is administered.

This hormone is called hCG (human chorionic gonadotropin) and is usually supplied between day 11 and 12 after the beginning of the hormonal treatment. Only one injection of this hormone is needed. HCG stimulates the release of oocytes 36 hours after its administration. For this reason, the follicular puncture should be performed at that time.

Endometrial epithelium

Endometrial preparation

Once the follicular puncture to retrieve oocytes is finished, the third stage of treatment, the endometrial preparation, should start. The endometrium needs to be prepared so when he transfer is ready the embryos can implant.

Around day 15 of treatment, the vaginal administration of progesterone begins and lasts for about 10 days. Progesterone increases the endometrial thickness and prepares the endometrium to receive the embryos.

Throughout the process of hormonal stimulation, support is available so the patient can discuss any concerns with specialists. The patient can lead a normal life during this process.

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