Which hormonal change is typically observed in the late mentrual reproductive years?

In the late menstrual reproductive years, a decline in inhibin levels is a typical hormonal change observed. Inhibin is produced by the ovaries and plays a critical role in regulating follicle-stimulating hormone (FSH) levels. As women approach menopause, the ovarian reserve decreases, leading to a reduced production of inhibin. This decline results in less negative feedback on the pituitary gland, causing FSH levels to rise in an attempt to stimulate the ovaries. Monitoring inhibin levels can provide insights into the functioning of the ovaries and the remaining follicular reserve.

In contrast, consistently high levels of AMH (anti-Müllerian hormone), a hormone that reflects ovarian reserve, would not be consistent with the late reproductive years, as AMH levels typically decline as the number of growing follicles decreases. Additionally, a high antral follicle count (AFC) is also indicative of good ovarian reserve, which is not expected in the late reproductive phase as this count tends to diminish. Lastly, estradiol levels do not steadily increase; instead, they can fluctuate but do not show a consistent rise as women transition toward menopause.