Ovarian stimulation: The first stage of the IVF procedure

Ovarian stimulation is a key first step in the in vitro fertilisation (IVF) procedure. It aims to obtain more mature ova, which can then be used in the fertilisation process. With stimulation, the chances of success of the entire IVF procedure are increased. Importantly, the success of this stage is most influenced by its proper planning and adaptation to the woman’s individual situation. Stimulation should always be designed after a detailed consideration of the needs and results of the individual patient.

Purpose of ovarian stimulation

During a woman’s natural menstrual cycle, usually one egg cell matures in the ovaries within a month. In the IVF procedure, the aim is to obtain multiple ovarian follicles containing mature egg cells, which increases the chances of obtaining healthy embryos. For this reason, the first stage is known as stimulation. Sometimes it is preceded by taking contraception in order to regulate and calm the previous hormonal processes.

How does ovarian stimulation work?

  1. Hormonal medication
    • The woman takes hormonal medication, such as gonadotropins, for about 10-14 days. These drugs stimulate the ovaries to produce more ovarian follicles containing egg cells.
  2. Cycle monitoring
    • Regular ultrasound and blood tests are essential to monitor ovarian follicle development and hormone levels. This allows doctors to adjust medication doses and monitor when follicles have reached the right size.
  3. Preventing premature ovulation
    • To prevent premature ovulation, additional drugs, GnRH agonists or antagonists are used. These allow the ovarian follicles to mature evenly and be ready for punction at the optimum moment.
  4. Induction of ovulation
    • When the follicles reach the appropriate size, the woman receives an injection of a so-called trigger, such as hCG (human chorionic gonadotropin), which induces the final maturation of the egg cells and prepares them for retrieval.

Risks and complications

Ovarian stimulation carries certain risks, the most important of which are:

  • Ovarian hyperstimulation syndrome (OHSS): A rare but serious reaction to stimulant drugs, leading to ovarian enlargement and fluid accumulation in the abdomen and chest.
  • Allergic reactions: allergic reactions to the hormonal drugs used may occur.
  • Stress and discomfort: Hormone injections (injections) and frequent visits to the doctor can be stressful and cause physical and emotional discomfort.

Preparation for ovarian stimulation

Preparation for ovarian stimulation includes:

  • Medical consultation: Discuss the treatment plan, expectations and potential risks with the doctor.
  • Pre-testing: Hormonal testing, ovarian ultrasound and other diagnostic tests to assess the patient’s overall health and readiness for the procedure.


Ovarian stimulation is the first and extremely important step in the IVF procedure. It makes it possible to obtain a greater number of mature oocytes, which increases the chances of success of the entire in vitro fertilization procedure. Proper monitoring and adjustment of treatment by an experienced medical team minimizes risks and increases the chances of obtaining healthy embryos. For more information on the IVF process and the various stages of the procedure, see the article “IVF: What is it and how does it work?”