A low FSH level can occur due to hormonal imbalance involving the brain, pituitary gland, stress, excessive weight changes, or certain medical conditions. Treatment depends on the exact cause rather than simply increasing the FSH number itself. Doctors may perform additional hormone tests and scans to understand whether ovulation and other reproductive hormones are functioning normally. In some cases, fertility medicines or hormone injections may be prescribed if pregnancy is being planned. It is important not to start hormone medicines on your own because incorrect treatment can disturb the menstrual cycle further. Proper evaluation by a gynaecologist or endocrinologist is the safest way to decide treatment.