Intra-cycle fluctuations of anti-Müllerian hormone in normal women with a regular cycle: a re-analysis

Anti-Müllerian hormone (AMH) has emerged as an important marker of ovarian reserve. Its variation throughout the cycle, however, may still be a matter of debate. The objective of this study was to re-evaluate the intra-cycle fluctuations of AMH in individuals in a prospective clinical study with focus on the age-related effects on these fluctuations. Frequent blood samples were obtained from the mid-luteal phase of the first cycle to the mid-luteal phase of the second cycle in 44 healthy, regularly menstruating Caucasian women. Main outcome measures were individual fluctuations of AMH concentrations during the natural menstrual cycle. AMH concentrations exhibited large fluctuations throughout the cycle and did not follow a defined pattern. Female age was negatively correlated with mean AMH concentrations. The absolute intra-individual variation was also negatively associated with age, whereas the relative intra-individual variation was positively associated with age. Although the fluctuation in relative intra-individual variation was higher in the older group, the absolute variation is very low and these fluctuations might therefore be of limited clinical relevance in this age group. These data show that in younger women caution should be exerted with the interpretation of a single randomly taken AMH measurement as a representative of ovarian reserve.Anti-Müllerian hormone (AMH) is currently under investigation to evaluate its use as a marker for the number of eggs remaining in the ovary, also known as the ovarian reserve. Ovarian reserve is used for decision making in infertility treatment. Some say it is a reliable marker that can be measured once at any time in the cycle; others claim that AMH fluctuates throughout the menstrual cycle. The aim of the current study was to evaluate whether AMH fluctuates during the cycle and whether the amount by which it fluctuates is dependent on the age of the individual. To investigate this, we took frequent blood samples during two cycles in 44 healthy, regularly menstruating women. In conclusion, AMH concentrations showed large fluctuations throughout the cycle but did not follow a defined pattern. The AMH concentration decreased with age. The amount of fluctuation was larger in younger women. These data show that, in younger women, caution should be exerted if a single randomly taken AMH measurement is used for clinical decision making.