Complex sentence: The menopausal transition is characterized by marked, and often dramatic, variations in FSH and estradiol levels, and because of this, measurements of these hormones are "not" considered to be reliable guides to a woman's exact menopausal status.
Split into simpler sentences: The menopausal transition is characterized by marked, and often dramatic, variations in FSH and estradiol levels. Because of this, measurements of these hormones are "not" considered to be reliable guides to a woman's exact menopausal status.