Hormone stimulation of the ovaries
Hormonal stimulation (ovulation stimulation) is a procedure involving the use of appropriately selected pharmacological agents to increase the number of mature, fertilisation-capable ova in the ovaries.
When is hormonal ovarian stimulation necessary?
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Stimulating the ovaries to produce ovarian follicles is essential for women who do not ovulate at all, because without ovulation they have no chance of becoming pregnant.
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Pharmacological ovarian stimulation is also used by patients in whom, despite regular ovulation, fertilisation does not occur (this is known as controlled hyperstimulation).
Why ovulation stimulation for IVF?
It is worth realising that not all oocytes have the chance to give rise to a new life. Statistically, 7-8 embryos are obtained from 10 fertilised oocytes, of which only 3-4 are properly formed and suitable for transfer or freezing.
When hormonal ovarian stimulation is used, IVF yields better results because more than one dominant follicle is formed per cycle and doctors have more mature oocytes available.
Ovulation stimulation before IVF
Hormonal stimulation of ovulation (ovulation stimulation) contributes to a marked increase in the effectiveness of the intrauterine insemination and in vitro fertilisation procedures, which is why most couples undertaking infertility treatment opt for ovulation support.
Hormone stimulation of the ovaries follows strict rules - the so-called stimulation protocol is chosen individually, taking into account such data on the woman as:
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age,
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weight,
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the concentration of anti-müllerian hormone (AMH) in the blood,
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the result of a vaginal ultrasound examination.
The procedure generally takes 7-12 days, as this is how long it takes for the ovarian follicles to mature in the ovary.
When the follicles have reached the right size (more than 17 mm) and a blood test shows the correct oestradiol concentration, the patient receives a subcutaneous or intramuscular injection with hCG, which induces first maturation and then ovulation, i.e. the release of the resulting ova.
Ovulation stimulation must always be carried out under control
During hormonal stimulation for IVF, the woman is under constant medical observation, as it is necessary to monitor the growth of the ovarian follicles on an ongoing basis (the so-called 'ovarian growth monitoring'). cycle monitoring). During the 2-4 follow-up visits, an ultrasound is performed and hormone concentrations are measured in order to assess the body's response to the administered medication and to determine the optimal moment for egg retrieval.
| Did you know that. The effectiveness of a correctly selected stimulation protocol depends neither on its type (long protocol, short protocol, with antagonist, etc.) nor on the hormonal drugs used, but is an individual issue. Therefore, it does not make sense to compare stimulation drugs prescribed by different doctors between different patients. |
Side effects of ovarian stimulation
Hormonal drugs to stimulate ovarian follicle production are short-acting and generally do not cause unpleasant side effects, but they must be administered under the close supervision of a doctor who will assess the number of ovulatory follicles and determine whether they are all growing properly.
It is accepted that the normal number of antral follicles (3-10 mm in diameter) is 5-15 in each ovary, while larger numbers, such as 20-30, may indicate polycystic ovarian syndrome. This condition can pose a serious risk to a woman as ovarian hyperstimulation syndrome (OHSS) can occur as a result of hormonal medication.
Not bursting follicles despite medication is also a worrying symptom, as it can lead to the development of cysts on the ovaries.
Find out more about ovulation disorders >>
Ovarian hyperstimulation syndrome
The term ovarian hyperstimulation syndrome (OHSS - Ovarian Hyperstimulation Syndrome) is defined as a situation in which the ovarian follicles and ovaries enlarge uncontrollably, despite the cessation of stimulant medication, and systemic changes occur as a result of a number of substances secreted by the stimulated ovaries, including the movement of body fluids into spaces outside the blood vessels.
OHSS figures
Ovarian hyperstimulation (OHSS) can have one of four forms: mild, moderate, severe or critical.
| Mild form | If OHSS is mild, the woman experiences tightness or soreness in the lower abdomen, sometimes nausea; a few days after stopping the hormone medication, these symptoms resolve spontaneously as the hormone concentration in the blood gradually decreases. |
| Moderate course | Moderate ovarian hyperstimulation syndrome causes, in addition to the symptoms mentioned in the mild course, enlargement of the abdominal girth, vomiting or diarrhoea; pain becomes more severe. |
| Severe hyperstimulation | Women who present with the severe or critical form of OHSS experience very significant ovarian enlargement, ascites and respiratory distress. If not under medical care, they are at risk of circulatory failure, clotting disorders and even death. |
Factors that increase the risk of ovarian hyperstimulation include:
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young age,
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slim body build,
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high ovarian reserve,
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polycystic ovary syndrome.
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Medical consultation of the article: doctor. Robert Gizler, gynaecologist-obstetrician, medical director of the Invimed clinic in Wrocław. Member of the Polish Gynaecological Society (PTG), the Polish Society of Reproductive Medicine and Embryology (PTMRiE) and the European Society of Human Reproduction and Embryology (ESHRE).
