Occurrence of postmenopausal-like acidic follicle-stimulating hormone (FSH) isoforms precedes the rise of FSH before menopause  Chris M.G. Thomas, Ph.D., Paul N. Span, Ph.D., Jesper M.J. Smeenk, M.D., Ph.D., Rob G.J.M. Hanssen, Ph.D., Didi D.M. Braat, M.D., Ph.D., Fred C.G.J. Sweep, Ph.D.  Fertility and Sterility  Volume 92, Issue 2, Pages 613-619 (August 2009) DOI: 10.1016/j.fertnstert.2008.06.012 Copyright © 2009 American Society for Reproductive Medicine Terms and Conditions

Figure 1 Distribution of FSH and LH glycoforms in seven cyclic women aged 20 to 25 years with FSH <10 IU/L on cycle day 3. Fertility and Sterility 2009 92, 613-619DOI: (10.1016/j.fertnstert.2008.06.012) Copyright © 2009 American Society for Reproductive Medicine Terms and Conditions

Figure 2 Comparison of the median (25 and 75 percentiles) relative cumulative percent rates of (A) FSH glycoforms at pI >4.3 and (B) LH glycoforms at pI >6.5 for women aged 20 to 25 years versus women aged 40 to 45 years. Black squares with solid lines are from young women (aged 20 to 25 years), open squares with dotted lines are from older (40 to 45 years) women with normal early follicular FSH levels. Fertility and Sterility 2009 92, 613-619DOI: (10.1016/j.fertnstert.2008.06.012) Copyright © 2009 American Society for Reproductive Medicine Terms and Conditions

Figure 3 Box-plots of relative levels of (A) FSH > pI 4.3 and (B) LH > pI 6.5 in premenopausal women (age 20 to 25 years, 40 to 45 years with normal early follicular FSH [N], 40 to 45 years with higher early follicular FSH [H]) and women with premature ovarian failure (POF) and postmenopausal women (PM). For FSH, a decrease in levels is seen during aging that is already statistically significantly different in older women before FSH rises. Boxes represent mean of levels of all cycle phases of premenopausal women. Fertility and Sterility 2009 92, 613-619DOI: (10.1016/j.fertnstert.2008.06.012) Copyright © 2009 American Society for Reproductive Medicine Terms and Conditions