Detailed inform­a­tion and a list of ref­er­ences can be found in Chapter 3.5 of the FertiPROTEKT book, “Indic­a­tions and fertility pre­ser­va­tion methods for onco­lo­gic­al and non-onco­lo­gic­al disorders”, which can be down­loaded free of charge.


GnRH agonists (GnRHa) are drugs which tem­por­ar­ily prevent the release of the hormones LH and FSH from the pituitary gland, which normally stimulate oocyte mat­ur­a­tion and hormone pro­duc­tion in the ovaries. Sup­pres­sion of hormone pro­duc­tion in the ovaries should reduce the sens­it­iv­ity of the ovarian tissue to chemo­ther­apy and therefore the like­li­hood of damage. The use of GnRHa has long been crit­ic­ally discussed. The reasons for this are that a pro­tect­ive effect has not been def­in­itely proven and the — also unproven — assump­tion that the reduction in hormone pro­duc­tion in the ovaries with hormone-dependent tumours (e.g., some forms of breast cancer) could also reduce the desired effect of chemo­ther­apy on tumour cells.

GnRHa are usually admin­istered sub­cu­taneously as a 1- or 3‑month depot injection about a week before chemo­ther­apy. The injection is then repeated as needed so that the effect lasts for the duration of chemotherapy.

Birth control pills are not further con­sidered here, since no major current studies are available which have analyzed their efficacy with regard to fertility pre­ser­va­tion to a suf­fi­cient extent and quality.


Most summaries of studies since 2011 show that by using GnRHa, the prob­ab­il­ity of a permanent sup­pres­sion of ovarian function after chemo­ther­apy is con­sid­er­ably reduced. .

Some studies also describe a higher pregnancy rate after the end of treatment in women who received GnRHa simultaneously.


GnRHa can cause men­o­paus­al symptoms such as hot flushes, etc. The con­ceiv­able loss of bone density when used for > 6 months is usually irrel­ev­ant because the duration of chemo­ther­apy does not normally exceed this length of time.

There is currently no evidence that GnRHa could the­or­et­ic­ally decrease the effect­ive­ness of chemo­ther­apy in hormone receptor-positive tumours.


The cost of GnRHa over one month is about 180 € and the total cost alongside 6 months of ongoing chemo­ther­apy, for example, is approx­im­ately 6 x 180€.  The costs are only covered by health insurance in excep­tion­al cases.


GnRHa are injected sub­cu­taneously for the first time about a week before chemo­ther­apy. The drug is given repeatedly during the course of chemo­ther­apy, so that its effect lasts for about 1–2 weeks after the end of the last chemotherapy.

If chemo­ther­apy must be started within less than a week in urgent cases, the effect of GnRHa can be supported by the addi­tion­al short-term use of a related drug (so-called GnRH-ant­ag­on­ists). Chemo­ther­apy can then, for example, begin on the day after the first injection.