Functional Hypothalamic Amenorrhea (FHA)

Functional hypothalamic amenorrhea is the loss of periods that follows when the hypothalamus slows its signal. The hypothalamus is the part of the brain that starts the cycle. Stress, weight loss or heavy exercise can slow it. No organ is damaged, and the signal can return. Clinicians reach the diagnosis by ruling out other causes.¹

Absent periods are the visible end of a wider pattern. Long cycles, skipped ovulation and short luteal phases come from the same suppression. They hide inside cycles of ordinary length. One study of more than 3,000 Norwegian women with normal cycle lengths found such a subclinical ovulatory disturbance in 24 to 37 percent of cycles.²

The cause is the target: food intake, training load and stress. Dietary and mental health support sit beside medical care.¹