AMH is produced by primary, secondary and early antral follicles and its concentrations do not vary throughout the menstrual cycle ( Cook et al., 2000 La Marca et al., 2004 Hehenkamp et al., 2006). Apart from increased EFP FSH levels, anti-Müllerian hormone (AMH) has been suggested to be an early marker of female reproductive ageing ( De Vet et al., 2002 van Rooij et al., 2002 Fanchin et al., 2003). In a previous study ( De Koning et al., 2000), higher FSH and LH pulse amplitude and response to GnRH in a group of women with elevated Day 3 FSH levels were found in combination with lower inhibin A and inhibin B levels. It is assumed that decreased negative feedback from the diminishing number of pre-antral and early antral follicles plays a major role with regard to this FSH rise.

More recent investigations have shown that serum inhibin B levels are decreased in the EFP in older women ( Klein et al., 1996, 2004 Danforth et al., 1998 Welt et al., 1999 Muttukrishna et al., 2000) and also in younger women with elevated FSH levels ( De Koning et al., 2000). This monotropic rise of FSH levels in the EFP has been described by a number of authors ( Sherman et al., 1976 Reyes et al., 1977 Lee et al., 1988) in ageing ovulatory women. Ovarian aging, AMH, elevated FSH, intercycle variation FSH, inhibins and ageing IntroductionĮlevated early follicular phase (EFP) serum levels of FSH have been used in recent years to counsel patients in infertility treatment, because this is associated with poor response in ovarian stimulation and subsequent low pregnancy rates ( Scott and Hofmann, 1995).

10 day follicular phase