Hormones in IVF: what are the medications used and why?

What hormones are used to stimulate ovulation in the context of IVF?

Before committing to an in vitro fertilization (IVF) program, many women have questions about the necessary medications, their effects on the body, and potential side effects. Hormonal stimulation of ovulation is one of the key steps in the procedure, allowing for the retrieval of multiple mature eggs, which significantly increases the chances of successful fertilization.

The main hormones used in IVF

The IVF process involves controlled ovarian stimulation aimed at maturing several oocytes, which will then be fertilized in the laboratory by the partner's sperm. To achieve this, hormonal medications are used to regulate the reproductive system.

Before starting the program, the woman undergoes a comprehensive examination including

• Hormone level tests: FSH, LH, AMH, estradiol, progesterone, TSH, prolactin;
• A pelvic organ ultrasound to assess the condition of the ovaries and endometrium;
• evaluation of general health status.

Based on this data, the specialist develops an individual stimulation program, monitoring hormone levels at each stage. If necessary, the dosage is adjusted based on ultrasound results.

Gonadotropins and their role in IVF

Gonadotropins are hormones produced by the anterior lobe of the pituitary gland that regulate the sex glands and the ovulatory and menstrual cycle. The main gonadotropins are

• Follicle-stimulating hormone (FSH) - stimulates the growth and development of follicles in the ovaries.
• Luteinizing hormone (LH) - responsible for the final maturation of the egg and ovulation.

Gonadotropin-releasing hormone (GnRH) and its regulation

The hypothalamus produces gonadotropin-releasing hormone (GnRH), which is released into the blood every 1.5 to 2 hours, stimulating the production of gonadotropins by the pituitary gland. This process is regulated by a feedback mechanism: when gonadotropin levels rise, GnRH secretion is halted, helping to maintain hormonal balance.

Synthetic analogs of GnRH are used in reproductive medicine:

• GnRH agonists - initially cause a brief spike in gonadotropin production, then suppress their secretion, which helps prevent premature ovulation.
• GnRH antagonists block gonadotropin production all at once, allowing for control of follicle maturation and reducing the risk of early ovulation.

Other important hormones in IVF

• Progesterone and estrogens prepare the endometrium for embryo implantation, facilitating the attachment of the embryo to the uterine wall. Normally, these hormones are produced by the corpus luteum and, after pregnancy, by the placenta.
• Human chorionic gonadotropin (hCG) - acts as a trigger for ovulation. The introduction of hCG completes the maturation process of the oocytes and, after 40-42 hours, the follicles are aspirated and prepared for fertilization.

Hormonal context control during IVF

Throughout the IVF program, the woman undergoes regular hormonal tests and ultrasound monitoring. This allows for the control of the follicle maturation process and adjustments to stimulation if necessary.

It is important to understand that competent ovulation stimulation must be performed under the supervision of an experienced physician, as overstimulation can lead to complications such as ovarian hyperstimulation syndrome (OHSS).

Individual approach to hormonal stimulation

Each patient has hormonal particularities, so stimulation protocols may vary by individual. At the "Natuvitro" clinic, specialists develop personalized stimulation protocols, ensuring the safety of the procedure and the retrieval of high-quality eggs. This approach significantly increases the chances of successful fertilization and pregnancy.