Female fertility preservation: clinical challenges

This thesis describes several studies focused on clinical challenges in female fertility preservation. First we presented a cross-sectional study that shows an overview of the reasons women banked oocytes in our centre and revealed that most women did so because of age-related decline of fertility. We explored the preferences of women who face age-related fertility decline. Overall, women considered oocyte banking as relatively ‘easy’, whereas ovarian tissue banking was seen as a more invasive procedure and therefore most women preferred oocyte banking over ovarian tissue banking. We reported reproductive outcomes of women who banked oocytes for fertility preservation and found that most women conceived naturally. We provided guidance by recommendations for handling fertility preservation for mother-to-daughter oocyte donation requests. We present a prospective case-series of four women with estrogen positive breast cancer in which we assessed their tamoxifen metabolite levels during ovarian stimulation with additional tamoxifen for fertility preservation. We concluded that therapeutically effective endoxifen serum levels can be reached, when tamoxifen is used to counteract estrogen levels, but not in all women. Finally we presented the results of a randomized controlled trial on the effectiveness of various controlled ovarian stimulation protocols in terms of oocyte yield in women with breast cancer undergoing fertility preservation. In this study, 162 women were randomly assigned to either ovarian stimulation plus tamoxifen, ovarian stimulation plus letrozole or standard ovarian stimulation. The primary outcome, number of cumulus oocyte complexes retrieved, did not differ between ovarian stimulation with tamoxifen or letrozole versus standard ovarian stimulation.