Ovarian stimulation to collect egg cells

Detailed information and a list of references can be found in Chapter 3.1 of the FertiPROTEKT book, "Indications and fertility preservation methods for oncological and non-oncological disorders", which can be downloaded free of charge.


The aim of egg cell maturation treatment (stimulation) is to produce mature egg cells (oocytes) that can be frozen either fertilized unfertilized. This method should be performed as quickly as possible as part of the necessary treatment of the underlying disease. Often, only one attempt is possible in the time available, and this should proceed as optimally as possible to collect the maximum number of mature egg cells without increased risks.

It is important that embryos can only be transferred later with the consent of the partner. However, since the cells may be stored for several years it must be considered that if the couple are no longer in a relationship, then the fertilized egg cells cannot be transferred. To avoid this risk, "splitting" is advised (50% of egg cells frozen fertilized, 50% frozen unfertilized), even for patients in a stable relationship, to ensure the woman’s independence.

Stimulation treatment started at the time of menstruation is a routine procedure.



The number of oocytes collected depends on the age and the ovarian reserve of the woman and must be assessed individually by the physician. The average number of egg cells is according to the FertiPROTEKT register is ca.12 in women who are younger than 36 and 8 at 36-40 years of age. The freezing of unfertilized egg cells has only slightly lower fertilization rates and pregnancy rates than freezing of fertilized ova.



The costs of egg cell collection are slightly different depending on the centre and are broken down approximately as follows:

  • drug costs (depending on the required dose and duration of treatment): 1500 to 2000Euros
  • stimulation method (ultrasound monitoring, oocyte retrieval): 1000 to 1500 Euros
  • freezing and storage for 1 year: 400 to 800Euros

If the couple are married, a health insurance application can be issued (in Germany) at short notice, so that the costs are entirely or partially (depending on the insurance status) covered.




To make oocyte collection possible, oocyte maturation must be stimulated by hormones. Injections are used for this which patients can administer themselves for 10-12 days, after tuition. To prevent undesirable premature ovulation, a second injection is added during the course of treatment, so that 2 injections are administered every day for about 5 days. The dose is adjusted where necessary according to regular ultrasound examinations, which are usually performed 2-3 times (every 2-3 days).


features of hormone dependent tumours

The situation in women with hormone receptor positive tumours, e.g. hormone receptor positive breast cancer, is a special situation because hormone production is stimulated during oocyte maturation, which could theoretically contribute to tumour growth. To reduce the increase in estrogen levels during treatment, the addition of special drugs which inhibit estrogen production is recommended. Since these so-called “aromatase inhibitors” are not approved for ovarian stimulation and the treatment is "off-label" (i.e. prescription at cost price). Previous studies have not demonstrated any increased malformation rates in children who were conceived using this method.


combination of egg cell collection with removal of ovarian tissue

In treatments where there is a high probability of the ovarian function being damaged, oocyte collection can be combined with the removal of ovarian tissue. Half an ovary should be removed during laparoscopy and oocyte stimulation can be started two days later. The data on such a combination of techniques has not shown any increase in complications. The number of collected oocytes does not appear to be reduced. The time required for the combined procedure is about 2.5 weeks.