Ovarian Reserve

Ovarian reserve is the pool of follicles that remain in the ovaries. Follicles are the small sacs in the ovary that hold eggs. Three markers estimate that pool: AMH, AFC, and basal FSH. No test can count eggs directly. These markers show the current level of follicle activity. They do not give a final verdict on fertility. A low AMH or a low AFC means that the visible pool is smaller than average. A low number does not explain the cause. It does not rule out natural conception. One study compared women with "unexplained" infertility to women whose infertility traced to a male factor. Low AMH was no more common in the unexplained group. The authors concluded that ovarian reserve does not predict natural conception.¹ Conception requires only one healthy follicle in a cycle.

AMH, anti-Müllerian hormone, comes from the small growing follicles. More of these follicles means more AMH. AFC, the antral follicle count, is the number of follicles that a clinician can see on an ultrasound early in the cycle. Basal FSH rises when the pituitary gland must work harder to grow a follicle. No single marker settles the question. Read together, the markers outline how the ovaries function at present.

Low markers are the start of a clinical question. A restorative approach asks why the number is low before it treats the number as the whole story. Thyroid function is one factor that clinicians check. Untreated thyroid disease can harm follicle health, and it responds to treatment. Thyroid antibodies alone, with normal thyroid levels, are a reason for continued monitoring. They are not proof of a treatable cause in this setting. Vitamin D is another marker that clinicians check. Studies on vitamin D and AMH disagree with each other. For this reason, correction of a true deficiency rests on its own merits. It does not rest on a promised rise in AMH. Endometriosis damages the ovary directly. Endometriomas, the cysts that endometriosis forms in the ovary, cause harm, and so does scar tissue. Careful excision treats that structural cause. A meta-analysis found that DHEA supplements were associated with higher AMH in women with low reserve. The association was weaker when the analysis counted only randomized trials.² Each of these factors is a lead worth pursuing. The search for a diagnosis still comes first.

For women with premature ovarian insufficiency (POI), reserve testing is one part of a wider workup. That workup also covers genetic and autoimmune causes. For women with diminished ovarian reserve (DOR) and no POI diagnosis, the first step is to identify the driver behind the numbers. Reserve markers carry more meaning when clinicians read them alongside cycle chart data, a follicle maturation study, timed hormone panels, and a whole-body workup.