Absence of Menstruation (Amenorrhea)

Amenorrhea is the absence of menstruation. Amenorrhea is divided into two categories: Primary and secondary amenorrhea. Primary amenorrhea refers to the absence of menstruation in a girl who has reached the age of 14 but has not yet shown signs of breast development or pubic hair growth, and has not started menstruating yet. However, if breast development and pubic hair growth have started, the age limit for diagnosing primary amenorrhea is 16. Secondary amenorrhea refers to the cessation of menstruation for three months in a row in a woman who has previously had menstruation.

In cases of absence of menstruation, the possibility of “pregnancy” should not be ignored.

The hypothalamus (a region in the forebrain located below the thalamus and forming the base of the third ventricle), pituitary gland, ovaries, and uterus function normally in a woman with regular menstrual cycles. The hypothalamus and pituitary in the brain stimulate the ovaries through the hormones FSH and LH). In response, the ovaries produce oestrogen and progesterone hormones, which then stimulate the lining of the uterus (endometrium) to enable menstrual bleeding. For a normal, regular menstrual cycle each month, a sequential mechanism among these organs is necessary. If this mechanism is disrupted at any stage, it can result in the absence of menstruation or menstrual irregularities. In addition, apart from these mechanisms, there must be no obstruction in the blood flow path (cervix, vagina, hymen) for menstrual bleeding to occur.

Causes of Primary Amenorrhea:

  • Pathologies or tumours in the hypothalamus and pituitary gland
  • Imperforate hymen (absence of an opening in the hymen)
  • Turner syndrome
  • Constitutional growth delay
  • Galactosemia
  • Transverse vaginal septum (a partition in the vagina)
  • Congenital absence or underdevelopment of the vagina, cervix, or uterus

Causes of Secondary Amenorrhea:

  • Physiological causes: Pregnancy, corpus luteum cyst, breastfeeding, menopause
  • Hypothalamus-related issues
  • Suppression of the hypothalamic-pituitary axis
  • Post-birth control pill amenorrhea
  • Stress and depression
  • Weight loss, extreme thinness, malnutrition
  • Pituitary disorders: Pituitary ablation (removal), Sheehan syndrome
  • Prolactinoma (hyperprolactinemia, excessive production of the milk hormone)
  • Uncontrolled endocrinopathies: Diabetes, hypothyroidism, hyperthyroidism
  • Polycystic ovary syndrome (PCOS)
  • Chemotherapy
  • Radiotherapy
  • Endometrial ablation (surgical removal of the uterine lining)
  • Intrauterine adhesions (Asherman’s syndrome)
  • Medication: Systemic steroids, danazol, GnRH analogues
  • Premature ovarian failure, early menopause
  • Sarcoidosis
  • Hyperandrogenaemia (increase in male hormones such as testosterone)

Diagnosis of Amenorrhea:

The primary methods for diagnosing amenorrhea include testing levels of FSH, LH, prolactin, and, if needed, thyroid hormones, as well as conducting an ultrasound examination. If a brain pathology is suspected, CT or MRI scans may be required. In some cases, procedures such as HSG (hysterosalpingography), SIS (saline infusion sonography), or hysteroscopy may also be required to observe the inside of uterus.