Assessment of Ovarian Reserve
Current reproductive function can be subdivided into whether it is apparently normal, absent, or compromised. When there is evidence of ongoing ovarian function, there are difficulties in the accurate assessment of whether there is damage, although measures of ovarian reserve can provide some data and are summarized in table 1. Measurement of Follicle Stimulating Hormone (FSH) in the early follicular phase shows significant inter-cycle variation and is a late indicator of reduced ovarian reserve. A high result, i.e. over 10 IU/L, even if not present on a repeated sample, remains an important indicator of at least some loss of ovarian reserve. Low Anti-Müllerian hormone (AMH), traditionally used to predict poor response to ovarian stimulation, is increasingly used to indicate diminished ovarian reserve and correlates well with antral follicle count.(35) It is important to realize that low AMH is not predictive of the inability to conceive in regular cycling women who are actively trying to become pregnant.(36,37) Recent data show the value of AMH in prediction of natural menopause, but its accuracy falls sharply with decreasing age.(38) While AMH can distinguish categories of gonadotoxic risk in AYA cancer survivors its use in predicting duration of future fertility is unclear (39,40). Furthermore, concurrent treatment with exogenous hormones, either as replacement or as contraception, makes FSH levels uninterpretable and may suppress AMH by up to 30%.(41) As such, there are few reliable measure of ovarian reserve that can aid in predicting future fecundity in AYA survivors. The ideal variable would progressively decrease in a linear manner and allow for a window of time after crossing a threshold when oocyte preservation might be attempted after cancer treatment. It may be more helpful to trend measures such as AMH over time. Additionally, due weight should be given to predicted fertility risk based on therapy received.(42) Conversely, it is also essential to discuss the need for contraception when patients are at risk of unplanned and unwanted pregnancy.