The primary aim of this trial is to compare two groups of women undergoing IVF (IVF=in vitro fertilisation ) treatment, to investigate if assessment of AMH (AMH=Anti-Müllerian hormone ), in addition to assessment of maternal age, AFC (AFC=antral follicle count ) and BMI (BMI=body mass index ) gives a more optimal COH (COH=controlled ovarian stimulation than does assessment of only age, AFC and BMI, measured as number of patients obtaining 5-12 oocytes during COH.