15 Common Causes of Delayed Periods


Delayed periods are often the first sign of pregnancy, but dozens of other causes can explain why your period didn’t come down on the expected day.

In general, a few days of menstrual delay can occur even in women with a regular menstrual cycle, without this having any clinical relevance.

In non-pregnant women, even when the period decides not to come in a certain month, the chance of this being something important is small. Stress, miscalculations, changes in the contraceptive method, urinary tract infections and other minor situations are usually the most common causes.

However, when menstruation does not go down for three consecutive months, we consider that the woman has amenorrhea. In this case, once pregnancy is excluded, some illnesses may be behind the cessation of menstruation.

Main causes

In this article, we’ll cover 15 common causes of missed periods. Are they:

  • Pregnancy.
  • Stress and anxiety.
  • Discontinuation of the contraceptive pill.
  • Infections or diseases.
  • Calculation errors.
  • Recent changes in body weight.
  • Obesity.
  • Excessive thinness or eating disorders.
  • Excessive physical activity.
  • Thyroid problems.
  • Breast-feeding.
  • Polycystic ovary syndrome.
  • Menopause.
  • Recent start of the menstrual cycle.
  • Amenorrhea .

So if your period is late, see what situation you fit into.

Main causes of menstrual delay


Every sexually active woman who has a missed period must necessarily think about pregnancy. Pregnancy should be the first hypothesis to be ruled out, even in women who report using contraceptive methods, such as a condom or contraceptive pill.

The cessation of menstruation is usually the first symptom of pregnancy . However, since about 1/3 of pregnant women experience small escape bleeds in the first trimester of pregnancy , many women find that their period is coming normally.

So if your period was delayed a few days, and shortly thereafter you had vaginal bleeding other than what you are used to during your period, pregnancy could be the cause.

Don’t expect to get nausea, enlarged breasts, food cravings, abdominal pain, or increased urinary volume before you’re off your period. The menstrual delay usually appears at 3 or 4 weeks of pregnancy, while the other symptoms usually appear only after the 4th or 5th week.

There is no safer way to confirm or rule out an ongoing pregnancy than to take a pregnancy test . Current tests are already able to identify a pregnancy with only one day of missed period. However, exams are more reliable if performed after a week of delay. The BhCG blood test is the most reliable test, but the drugstore pregnancy test is easier to do and also has a high success rate.

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stress and anxiety

The menstrual cycle is easily influenced by factors external to the reproductive system. Emotional factors are enough to delay your period for a few days. Excessive stress or anxiety can negatively affect your hormone production, which is regulated by the hypothalamus, a part of the brain. Stress can even make you not ovulate in a certain cycle, suspending your period this month.

When we talk about stress, situations common to many people are included, such as excessive work, professional, financial or family problems, an important test in the short term, defense of a thesis, sick child at home, etc. Sudden changes in working hours, such as the constant need to work at dawn, can also disrupt the sleep cycle and interfere with the normal ovulatory cycle.

If you don’t want to get pregnant right now, and something went wrong in one of your sexual relationships, such as breaking a condom or forgetting to take the pill correctly, the stress generated by the risk of getting pregnant can also be great enough to delay the menstruation.

This process can even snowball as anxiety leads to missed periods, which in turn causes even more anxiety. The ideal in these cases, if your period is already 2 or 3 days late, is to take the pregnancy test right away to break this vicious cycle.

Discontinuation of the contraceptive pill

Women who take oral contraceptives correctly menstruate regularly. However, if after a few years of using the pill, you decide to suspend it, it is possible that your natural cycle will take some time to normalize.

There are women who go into amenorrhea and go months without ovulating after stopping the contraceptive. Eventually, menstruation will return, with no risk of infertility. Just be patient, the ovulatory cycle will naturally reorganize between 3 to 6 months.

However, it is worth noting that every woman with more than 3 months of missed period should seek advice from her gynecologist.

Post-contraceptive amenorrhea can occur with all forms of administration, including implants, injections or pills.

Infections or Diseases

Being sick can cause menstrual delay. It doesn’t have to be a serious illness such as a heart attack, tuberculosis or hepatitis. Common viruses like the flu, or simple infections like cystitis or tonsillitis can be enough to disrupt your menstrual cycle, delaying your period for a few days.

Some medications can also influence the hormonal cycle, disrupting your menstruation. Among the most common we can mention:

  • Antipsychotics.
  • Corticosteroids .
  • Antidepressants .
  • Chemotherapy.
  • Immunosuppressants.
  • Antihypertensives .
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Note: the use of antibiotics, in general, does not cause menstrual delay. What usually interferes with the menstrual cycle is the infection for which the antibiotic was prescribed.

Calculation errors

Women with an irregular menstrual cycle may have some difficulty figuring out the day when menstruation should start. You may think your period is late, when in fact it will only come 2 or 3 days later. Even women with regular cycles can occasionally have a period a few days late, for no reason. Your uterus has no fixed calendar, it is not required to act like a clock every single month.

Recent changes in body weight

Gaining a lot of weight or losing it in a short period of time is also a cause of dysregulation in the menstrual cycle. Our body’s fat cells contribute to the production of estrogen, the female hormone responsible for the maturation of eggs. Sudden changes in the amount of fat in the body acutely alter estrogen levels, which can interfere with ovulation and, consequently, with the date of menstruation.


This cause is a variation of the above situation. Overweight women have a large mass of fatty tissue, which causes excessive estrogen production. This female hormone is necessary for ovulation, but if it is in excess it inhibits the release of the egg, causing anovulatory periods. Without ovulating, a woman does not menstruate.

Excessive thinness or eating disorders

Another variation of nº5. The lack of fatty tissue also impairs the ovulatory cycle, as it reduces the female body’s ability to produce estrogen. Women who suffer from anorexia or are on extreme diets typically do not ovulate every month, presenting not only delayed menstrual periods but also a risk of amenorrhea.

Excessive physical activity

Women who exercise on a professional level also often experience menstrual changes. We are not talking about that physically active woman who goes to the gym frequently, but triathletes, marathoners, competitive swimmers, gymnasts and other professional sportsmen.

The high caloric expenditure, the stress of intense training and the low level of body fat seem to be responsible for the alterations in the menstrual cycle.

Thyroid problems

A thyroid that malfunctions (hypothyroidism) or overdoes it ( hyperthyroidism ) can also alter the menstrual cycle .

In general, uncontrolled thyroid problems can lead to amenorrhea. But, even in mild conditions or already treated with thyroid drugs, small changes in blood levels of thyroid hormones can disrupt the cycle and cause menstrual delays.

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If you’ve just had a baby and are breastfeeding, don’t wait for your period for the next few months. Breastfeeding does not cause a simple menstrual delay, but a transient amenorrhea, as the hormones responsible for milk production inhibit the return of ovulation. In general, menstruation usually returns as soon as the weaning process begins.

polycystic ovary syndrome

Women with polycystic ovary syndrome often have irregular menstruation because they produce too much androgens (male hormones). Menstrual delays and complete missed periods in a given month are very common in these cases. Women with this syndrome usually acquire excess weight, which, as we have seen, also contributes to menstrual delays.


The menopause usually arrives between 45 to 55 years. However, some women may experience menopause before the age of 45 years. There are still those who have early menopause , before the age of 40. One of the symptoms of impending ovarian failure is dysregulation of the menstrual cycle and the absence of ovulation in certain months. If you are over 35 and your period starts to linger and fail frequently, see your gynecologist.

Recent start of menstrual cycle

If your menarche (first menstruation) occurred recently, it is normal for your cycle to be irregular for the first few years. Menstrual changes can occur up to the first two years of menstruation, because the female reproductive system is still maturing. Therefore, menstrual delay at this stage is extremely common.


There are several causes for amenorrhea, including problems in the uterus, ovarian and even the brain glands that control the production of sex hormones, such as the pituitary and hypothalamus.

Amenorrhea is different from menstrual delay. If you have not had your period for three or more months, this can no longer be considered a missed period. Some causes of amenorrhea have been mentioned in this text, but there are several others.

So if you are not pregnant and your period has stopped coming, see your gynecologist as it is possible that there is some disease behind blocking your ability to ovulate.