Why Is My Period Late? 12 Possible Causes & What To Do

December 2021

A delayed period is not always a sign of pregnancy. Late periods can also be caused by other situations, like increased stress, hormonal changes or even excessive consumption of caffeine or alcohol.

Generally, this delay can last from a few days to 1 or 2 months. You should see your doctor if you are not pregnant and your period continues to be delayed for more than 3 months, as the cause should be identified and treated.

However, if you have a delayed period following unprotected sex, pregnancy is still a possibility. You should rule it out by completing  a home pregnancy test which can be purchased at a pharmacy.

Possible causes for a late period

If your period is late, you are advised to perform at least 2 pregnancy tests, with a 7-day interval between each test. If both of these yield negative results, likelihood of pregnancy is low, and the delay in period can be a result of other situations like:

  1. Excessive physical activity, which is frequent in athletes or people preparing for a sporting competition;
  2. Very restrictive diets;
  3. Poor diet or eating disorders such as anorexia or bulimia;
  4. Excessive stress;
  5. Ovarian changes;
  6. Diseases affecting the hypothalamus or pituitary gland;
  7. Hormonal changes caused by polycystic ovarian syndrome, endometriosis, fibroids or even by the morning-after pill;
  8. Continuously using a birth control pill;
  9. Recent curettage or surgery in the pelvic region;
  10. Proximity of menopause, or possibility of early menopause; 
  11. Postpartum phase, because menstruation should only return after the woman stops breastfeeding (although it is necessary to use contraceptive methods during breastfeeding);
  12. Side effect of a contraceptive: there may be no period for 6 months, or 1 year after the use of the quarterly contraceptive injection.

These situations can lead to the absence of your menstrual cycle for more than 3 months (amenorrhea). You are advised to see your doctor if this happens. 

Menstruation is also considered to be delayed when a girl who has reached the age of 16 has not yet menstruated for the first time. This is also known as primary amenorrhea and should be investigated by a gynecologist. This delayed period may be related to problems such as head trauma, prematurity or defects in the reproductive system such as an imperforate hymen, vaginal septum, or absence of a uterus.

What to do if your period is delayed

If your period is late, the first step is to complete out a pregnancy test from the pharmacy. If you haven’t had a period for more than 3 months and you cannot identify the cause, you should go to a gynecologist so that he or she can identify the cause and treat the problem. In some cases, the use of medication is recommended to stimulate your period. 

The doctor may order bloodwork to assess progesterone and prolactin levels, which may help to identify the reason for this delay and guide the most appropriate treatment.

Also, depending on what is causing your period delay, you may need to reduce the intensity of physical exercise, take it easy, avoid stress and maintain a varied and balanced diet rich in vitamins and minerals. These are all factors that contribute to a regular menstrual cycle.

It is also recommended that you see your doctor regularly to identify possible health problems or diseases such as polycystic ovaries, endometriosis, anorexia, bulimia, hyperthyroidism or hypothyroidism, all which can cause changes to your menstrual cycle.

How to regulate your menstrual cycle

There are certain measures that can help to prevent delayed periods and regulate the menstrual cycle, like:

  • A healthy lifestyle, with regular physical exercise and a healthy and varied diet, rich in fruits and vegetables;
  • Taking the contraceptive pill, as it can help to regulate the menstrual cycle;
  • Avoid extreme or restrictive diets, which, as well as doing harm to your health, end up making your menstrual cycle irregular;
  • Follow the indicated treatment if you have been diagnosed with Polycystic Ovarian Syndrome or thyroid disorders;
  • Maintain a healthy weight.

While these measures help to keep your cycles regular, you should still consult a doctor if you experience irregular periods.

When will my period come?

Report your cycle information below to calculate when your period is due:


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Edited by Tua Saude editing team in December 2021. Medical review completed by Dr. Sheila Sedicias - Gynecologist in November 2018.
Medical review:
Dr. Sheila Sedicias
Physician graduated in Mastology and Gynecology by UFPE in 2008 and member no. 17459 of CRM-PE, Brazil.