Why Does Menstruation Stop?

Menstruation, commonly known as a menstrual period, is a natural process in a woman's reproductive life. Most women expect their periods to occur regularly from puberty until menopause. However, sometimes menstruation may not begin at the expected age, may stop temporarily, or may cease altogether. The medical term for the absence of menstruation is 'amenorrhoea'. Amenorrhoea is one of the most common gynaecological problems seen in medical practice. It is not a disease by itself but rather a sign that something may be affecting the body's normal reproductive system. In some situations, the absence of menstruation is completely normal, while in others it may indicate an underlying health problem that requires medical attention.

To understand why periods stop, it is helpful to know how a normal menstrual cycle works. The menstrual cycle is controlled by a delicate interaction between the brain, hormones, ovaries, uterus, and reproductive tract. A part of the brain called the hypothalamus releases a hormone that stimulates the pituitary gland. The pituitary gland then produces follicle-stimulating hormone (FSH) and luteinising hormone (LH), which help the ovaries produce oestrogen and progesterone. These hormones prepare the lining of the uterus for a possible pregnancy. 

If pregnancy does not occur, the uterine lining is shed as menstrual bleeding. Therefore, normal menstruation depends on the proper functioning of the brain, hormone-producing glands, ovaries, uterus, and genital tract. A problem in any of these areas can result in amenorrhoea.

Amenorrhoea is classified into two main types, namely primary and secondary. Primary amenorrhoea refers to a situation in which a girl has not started menstruating by the age of 15 years despite having normal breast development and other signs of puberty. It may also be diagnosed when menstruation has not started by age 13 and there are no signs of puberty. 

And secondary amenorrhoea occurs when a woman who previously had menstrual periods stops menstruating for three months or more if her periods were regular or for six months if her periods were irregular. There are certain stages of life when the absence of menstruation is completely normal. These include before puberty, during pregnancy and breastfeeding and after menopause. These situations are known as 'physiological amenorrhoea' and do not usually require treatment.

Causes

When menstruation stops unexpectedly, there may be an underlying medical cause. Physical and emotional stress can affect the hormones that regulate menstruation. Severe stress, rapid weight loss, poor nutrition, eating disorders, and excessive exercise may suppress normal hormone production and stop ovulation. 

As a result, menstruation may cease. This is particularly common among athletes, dancers, and individuals with eating disorders. The hypothalamus and pituitary gland play key roles in regulating reproductive hormones. Certain conditions can interfere with their function, including brain tumours, head injuries, severe brain infections and radiation treatment. 

High levels of the prolactin hormone (hyperprolactinaemia) can also cause amenorrhea. This condition may result from pituitary tumours, certain medications, or thyroid disorders. Another rare condition is Sheehan syndrome, which can occur after severe bleeding during childbirth. Damage to the pituitary gland may lead to failure of breast milk production, fatigue and amenorrhoea. Polycystic ovary syndrome is one of the most common causes of menstrual irregularities in young women. The condition is associated with hormonal imbalance and failure of regular ovulation. Normally, the ovaries continue to function until menopause. However, in some women, ovarian function declines before the age of 40 years. This condition is known as premature ovarian insufficiency. The cause for POI may be genetic, autoimmune, related to cancer treatment, or sometimes unknown.

Some girls are born with abnormalities affecting the reproductive organs. For example, Turner syndrome may cause delayed puberty and primary amenorrhoea. Another condition called Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is characterised by the absence of the uterus despite normal development of breasts and other female characteristics. Sometimes menstruation stops because of damage to the uterine lining. A condition called Asherman syndrome can occur after uterine surgery, repeated dilatation and curettage (D&C) or severe uterine infections. In some girls, menstrual blood is produced normally but cannot leave the body because of a blockage in the reproductive tract. The most common example is an imperforate hymen, where the hymen completely covers the vaginal opening. Affected girls may have monthly abdominal pain but no visible menstrual bleeding.

Symptoms

The symptoms associated with amenorrhoea often provide clues about the underlying cause. So associated symptoms include nausea, breast tenderness, milky breast discharge, headaches and vision problems. Also, acne, obesity, hot flashes and vaginal dryness, and cyclical lower abdominal pain, suggesting an outflow tract obstruction to be reviewed to reach a diagnosis. So concerned specialists will approach the problem by taking a detailed medical history which follows a physical examination (including genital examinations). And several investigations will be carried out based on history and examinations. These include pregnancy tests, hormone tests, ultrasounds and blood tests for reproductive hormones. In selected cases, MRI scans, genetic testing, hysteroscopy or laparoscopy may be required.

Treatment depends entirely on the underlying cause. Some women may only need lifestyle changes such as improving nutrition, reducing stress, or achieving a healthy body weight. Others may require medications to correct hormonal imbalances or treat thyroid and pituitary disorders. Conditions such as PCOS often require long-term management, while structural abnormalities may need surgery. Women wishing to conceive may require specialised fertility treatment.

All sorts of amenorrhoea cases cannot be prevented, but the risk can be reduced by maintaining a healthy body weight, eating a balanced diet, avoiding excessive exercise, managing stress effectively and seeking early treatment for hormonal disorders. 

Conclusion

Amenorrhoea, or the absence of menstruation, is a common health concern that can occur for many reasons. While it is normal during pregnancy, breastfeeding, and menopause, it may also indicate an underlying hormonal, structural, or genetic problem. Because menstruation is an important indicator of a woman's reproductive health, persistent absence of periods should never be ignored. Early medical evaluation, accurate diagnosis, and appropriate treatment can help protect fertility, maintain bone health, and improve overall well-being.

(The author is a head of the Department of Obstetrics and Gynaecology at Dhulikhel Hospital.)