Amenorrhea: Causes

    Q: I had no period for 2 months. What could be the cause?

    A: It is called 'amenorrhea' if your period has not come for several months. If you previously had a menstrual period, then you have 'secondary amenorrhea,' and if you have never had a period, then it's called 'primary amenorrhea.'

    The No. 1 reason for secondary amenorrhea is pregnancy, and pregnancy as a cause should be excluded first. The only way to know whether you are pregnant or not is to do a pregnancy test. If the pregnancy test is repeatedly negative then you are not pregnant. In most cases of not having a menstrual period without being pregnant the reason for not getting a period is not ovulating (no ovululation = anovulation).

    Anovulation is usually caused by issues in the ovaries or centrally, in the brain. Other causes of amenorrhea include:

    • Problems in the vagina
    • Problems in the uterus

    The four most common causes of ovulatory dysfunction are:

    1. Polycystic Ovarian Syndrome (PCOS), which accounts for approximately 70% of ovulatory dysfunction cases. 
    2. Hypothalamic amenorrhea, also known as hypogonadotropic hypogonadism (approximately 10% of cases)
    3. Hyperprolactinemia (approximately 10% of cases)
    4. Premature ovarian failure, also known as hypergonadotropic hypoestrogenic anovulation (approximately 10% of cases)

    There are three distinct parts of the body that contribute to ovulation problems: the hypothalamus, the pituitary gland, and the ovaries.

    1. Hypothalamic problems (GnRH pulses FSH and LH)

    • Polycystic ovary syndrome
    • Prepubertal
    • Strenuous Exercise
    • Certain Diets
    • Stress
    • Low BMI, anorexia, sudden weight loss
    • Chronic or severe illnesses
    • Some drugs (e.g., opiates)

    2. Pituitary Causes

    • Hypothyroidism
    • Hyperthyroidism
    • Too much Prolactin. Prolactin may be increased with certain drugs (e.g. major tranquilizers). Any pressure on the gland such as certain tumors (prolactinomas) can also cause a rise in the prolactin hormone (hyperprolactinemia), which in turn can cause problems with ovulation.

    3. Ovary

    • Premature ovarian failure (POF)
    • Ovarian failure = menopause
    • Primary ovarian failure (often a chromosomal problem)
    • Secondary ovarian failure (cause often unknown, but can be due to an autoimmune disorder or caused by chemotherapy, radiotherapy, or surgery. The FSH is usually increased as there is no estrogen or inhibin feedback