I'm not Pregnant

Reasons you missed your period – Part 2

Причини за пропуснат менструален цикъл

In the previous blog, we discussed some of the main reasons for missing your period other than pregnancy – stress, intense exercises, PCOS, thyroid problems, etc. Here are some other reasons for lack of menstruation.


What is amenorrhea?

Amenorrhea means the absence of menstruation. There are two types of amenorrhea – primary and secondary. Primary amenorrhea is defined as the failure of initiation of the first menstrual cycle by age of 16. Secondary amenorrhea happens when a woman who has had normal menstrual cycles stops getting her monthly period for more than 3 months.

The menstrual cycle is regulated by the pituitary gland and the hypothalamus – structures of the brain than produce numerous hormones, including the gonadotropin hormones. Gonadotropin hormones cause the ovaries to produce sex hormones. Primary amenorrhea might result from hormonal imbalance, genetic conditions or congenital abnormalities of the reproductive system. Additional symptoms might be present such as pelvic pain, vaginal dryness, headache, etc. Your doctor might run a series of tests to diagnose primary amenorrhea.


Secondary amenorrhea occurs when a woman has had normal menstrual cycles stops getting her period for more than 3 months. Here are other reasons for secondary amenorrhea:


Premature ovarian insufficiency (POI)


Premature ovarian insufficiency (POI) is a failure of the ovaries to function adequately in women under the age of 40. This condition is characterized by a lack of menstruation (secondary menstruation), decreased serum levels of estrogens and elevated gonadotropic hormones. Premature ovarian insufficiency is associated with infertility, which, in contrast with the menopause, is reversible. Other health issues caused by this condition are early-onset osteoporosis and a higher risk of cardiovascular events. Approximately 0,1% of women aged under 30 and 1% of women under the age of 40 experience POI. Premature ovarian insufficiency may be caused by autoimmune diseases, genetic abnormalities, medications or radiation for cancer treatment, etc.


Hormonal imbalance


The main reason for skipping menstruation is hormonal disbalance. It can be a result of pituitary gland disorders, low levels of estrogens, elevated serum levels of testosterone (although this is the male sex hormone, it is also produced by women’s ovaries in small amounts) or overactive adrenal glands. For example, skipping menstruation can be caused by higher levels of prolactin. This is a hormone, produced by the pituitary gland. Prolactin causes the breasts to grow and produce milk during pregnancy and after birth. Prolactin levels are normally low for nonpregnant women and men. Higher levels are caused by pituitary adenoma, some medications, thyroid problems, PCOS, etc. This leads to irregular periods or no menstrual periods, milk discharge from the breasts when not pregnant or breastfeeding, lower libido, acne, etc.





Some medications such as antidepressants, antipsychotics and chemotherapy medications can cause amenorrhea. Other medications for high blood pressure and allergic reactions are also associated with amenorrhea. Valproic acid and carbamazepine, used for the treatment of epilepsy, are proved to cause irregular menstruations or amenorrhea. Also, women with epilepsy are three times more likely to have irregular menstrual cycles. On the other hand, sex hormones can impact on the disease. The progesterone drop just before menstruation is believed to be able to cause epileptic seizures. Additionally, antiepileptic drugs can decrease the effect of contraceptive pills. Don’t forget to tell the doctor about all the medications you are taking!


Suppressing your immune system with corticosteroids


Corticosteroid drugs are used to treat numerous diseases by suppressing the immune system. Long-term treatment can cause Cushing’s syndrome. Cushing’s syndrome is associated with irregular menstruation and amenorrhea. Higher steroid serum levels suppress the production of gonadotropin hormones. Additionally, there might be an increase in the levels of testosterone is the female body.

Cyclophosphamide is another medication that suppresses the immune system. It is used to treat multiple sclerosis (MS). Women with MS that take cyclophosphamide took part in clinical research. The results confirmed that cyclophosphamide causes irregular menstruation or amenorrhea. Additionally, women had low ovarian reserve which means lower number and quality of the eggs.




Taking drugs (cocaine, heroin) or opioids (for example methadone) can lead to amenorrhea. This is caused by gonadotropin imbalance. 76 women with heroin addiction histories took part in the research. 50% of them reported irregular menstruation or amenorrhea when using the drug. Drugs can also change the duration of your period.


Adhesions on the uterus


Adhesions in the uterus, also known as Asherman’s syndrome, is a condition that occurs when scar tissue is formed inside of the uterine cavity. This leads to changes in the size and shape of the uterus. Uterine adhesions can be caused by an injury following a surgical procedure, Caesarean section, endometriosis, infections, etc. Adhesions restricted to the cervix may present with amenorrhea since the menstrual blood can’t be evacuated from the uterus. Asherman’s syndrome may lead to infertility.


Ovary removal surgery


Surgical removal of reproductive organs is most commonly done because of benign or malign neoplasms. Removal of both ovaries causes post-castration syndrome or surgical caused menopause. A sudden decrease in estrogens leads to amenorrhea. The clinical picture of the post-castration syndrome includes hot flushes, night sweats, depression, metabolic pathologies, higher risk of osteoporosis, etc. Sometimes, when surgically removing the uterus, ovaries might be preserved. This leads to less severe symptoms. Secondary amenorrhea, though, will be still present.


Other reasons for skipping your period


Chronic diseases such as cirrhosis, chronic kidney disease, acquired immune deficiency syndrome (AIDS), diabetes and pelvic inflammatory disease can cause amenorrhea. Other reasons are autoimmune diseases, radiation, alcoholism or heavy metal poisoning. If your period is late for more than 6 weeks, consult your doctor to make sure everything is okay.