This is done through a series of blood tests. Both these hormones are produced in the pituitary gland. Low levels of FSH may indicate that the pituitary gland is not releasing enough of this vital hormone which is necessary to stimulate the egg to ripen in the ovary. Low levels of LH may indicate that the egg is being stimulated to develop but, because LH levels are low, the egg is never released. Blood tests to check thyroid levels and prolactin levels also may be needed.
Elevated prolactin can cause irregular ovulation in some women.
Overproduction of either of these hormones in the adrenal gland or ovary can cause irregular ovulation. The plasm progesterone level is a blood test taken mid-way between ovulation and menstruation. Progesterone, the hormone produced by the ovary after ovulation, is responsible for triggering the build-up of the endometrial tissue or lining of the uterus which is essential if the fertilized egg is to implant and grow. The endometrial biopsy is a test used to evaluate this uterine tissue building up and thickening after ovulation. It usually is done after day 21 of the cycle.