Updated: 5 days ago
Amenorrhea is defined as the absence of menstruation. It may be classified into two types - primary and secondary. Primary amenorrhea occurs when one has not had the first menses by the age of 16 years. Secondary amenorrhea occurs when one has had menstruation before, but has not had one for at least 6 months. Oligomenorrhea refers to infrequent menstrual cycles occurring less than 6 to 8 cycles a year. In this article, we will discuss mainly secondary amenorrhea.
The science behind
To understand how menstruation occurs, we must first learn about some basic science and body parts involved. The hypothalamus, which resides in your brain, sends signals called the gonadotropin-releasing hormones (GnRH) to a gland called the pituitary gland. The pituitary sits at the base of your brain just behind your nose. When it receives signals from the hypothalamus, it then sends its own signals (called the luteinising hormones (LH) and follicle stimulating hormones (FSH)) to the ovaries which then produces sex hormones oestrogen and progesterone. Oestrogen and progesterone go on to regulate your menstrual cycles. This is known as the hypothalamus-pituitary-ovarian (HPO) axis. The photo below illustrates this cycle.
Therefore, your menstrual cycles are dependent on the level of sex hormones in your body, which depends on the signals sent by the pituitary gland and the hypothalamus sitting in your brain. Causes that affect any of these organs have potential to affect your menstrual cycles.
When a patient first presents with secondary amenorrhea, the doctor will usually do a urine pregnancy test to first rule out that the patient is not pregnant. This is one of the most common causes of secondary amenorrhea. It is also important to note that if you are currently breastfeeding, you might have irregular menstrual cycles too; you might not have your first period for at least a few months. If the patient is not pregnant or breastfeeding, then the doctor might recommend a workup to investigate the causes. They can be categorised according to the part of the HPO axis.
Causes may include stress, significant weight loss, rigorous exercises and long-term illnesses. The hypothalamus of the brain is very sensitive to stressors which include the above, and commonly the menstrual cycles will resume back to normal once these causes are identified and lifestyle changes are made. There are also other important red flags to rule out, such as tumours or infections of the brain that can affect the hypothalamus. If you experience any neurological symptoms, which include numbness, weakness, severe headaches, neck stiffness or nausea and vomiting, consult a doctor immediately.
Causes may include medications, kidney problems, and autoimmune causes such as thyroid problems. Likewise, any tumours or infections of the brain that affect the pituitary gland in the brain will affect the HPO axis too. If you experience any of the above neurological symptoms, or if you experience visual changes, do consult a doctor. If you have had any complications during childbirth, such as losing a great amount of blood, you might have had Sheehan’s syndrome, which causes damage to the pituitary. You may experience problems with producing milk for breastfeeding, feeling tired all the time, weight changes, hair loss, and changes to heart rate and blood pressure. Speak with your doctor if you are concerned about any of these symptoms.
Conditions that may affect the ovaries include genetic (e.g., Turner’s), autoimmune disorders or infections. Other causes that result in increased male sex hormones include polycystic ovary syndrome (PCOS), adrenal syndromes e.g., congenital adrenal hyperplasia (CAH) and Cushing’s syndrome as well as tumours.
Your doctor might perform a series of tests, including taking some blood samples or radiological investigations such as ultrasound, CT scan, and MRI.
Treatment options depend on the causes. For example, tumours might require surgery and a series of chemoradiation to reduce the size of the tumour. Other types of treatment include oral contraceptive pills to regulate the sex hormones oestrogen and progesterone. If you have not had your menstruation in at least 6 months, and if you suspect you might have any of these problems, do consult a doctor.