Why is my period late?

Menstruation cycles should be pretty regular. If you are experiencing irregularities, such as missed periods or regular spotting, it would be a good idea to see a doctor. There could be several reasons for a late period. If your period hasn’t arrived as normal you are probably asking yourself why is my period late.

A lot of people will assume a late period means pregnancy but this is not always the case. Hormonal imbalances, stress, effects of birth control, and thyroid issues are just some of the reasons that could cause a late period. Moreover, late periods are also far more common in women who have just begun menstruation and those women beginning menopause.

The average cycle of a woman’s period is every 28 days but healthy cycles can actually range anywhere from 21 to 35 days. Let’s look in depth at some of the reasons why a healthy cycle could be disrupted.


Women who are trying to get pregnant are anticipating missed periods. Pregnancy results in a halt on the menstrual cycle. why is my period late pregnancy

If you have been having sex and think there may be a chance you are pregnant you should take a pregnancy test. These days home pregnancy tests can detect the hormone produced during pregnancy, human chorionic gonadotropin, quite early. Keep in mind that false negatives can occur so you might want to repeat the test and make an appointment with your gynecologist.


Stress can take a major toll on the body. Hormones become imbalanced and this can result in illness and sudden changes in weight. Hypothalamic amenorrhea is when the hypothalamus, a part of the brain that controls hormones, is not functioning correctly. Adrenaline and cortisol, the stress hormones, are being released too often. This prompts the body to halt bodily functions that are deemed less important while in “survival mode.” This can have a major effect on your menstrual cycle. It is important to talk to a professional if you think too much stress and anxiety is impacting you negatively.

weight changes/excessive exercise

If you have gained or lost a significant amount of weight, especially over a relatively short period of time, your periods may not be coming regularly. A lot of women with eating disorders, such as anorexia nervosa or bulimia, actually stop ovulating. This can happen if your weight is 10% or more below what a healthy weight for your height should be. Obesity can also contribute to cycle changes because of resulting hormonal changes. Finally, excessive exercise can result in missed or late periods. Nature has designed it so that pregnancy is less likely to happen when the body is under a lot of physical stress.

Polycystic Ovary Syndrome (PCOS)

PCOS is when a woman’s body produces too much androgen, which is a male hormone. The androgen leads to cysts forming on the ovaries. Menstruation will usually become irregular if not completely stop. PCOS symptoms can also include weight gain, difficulty in losing weight, hair growth on the face and chest and possible fertility problems.

Birth Control

Birth control pills are an effective mode of hormonal birth control. why is my period late birth controlThe combined pill contains the hormones estrogen and progestin. They work in conjunction to halt ovulation. There is also a mini pill which contains progestin only. You should speak to a doctor about what the right method of birth control is for you. Since the pill is producing hormonal changes, it can take some time for your cycle to become regular. The usual estimate of time in establishing a regular cycle is 6 months. Injections and implants, two other modes of birth control, can also cause cycle irregularities due to the hormone changes.

chronic illness

Illnesses such as diabetes and celiac disease can cause missed periods. Blood sugar and hormones are linked so when blood sugar is not stable irregularity can occur. An inflammatory illness, like celiac disease, causes damage to the digestive system which means the body struggles to absorb important nutrients. When you aren’t getting proper nutrition, your period can be disrupted.

Thyroid problems

The thyroid works to regulate the metabolism. If your thyroid is overactive or under-active your hormonal balance can be thrown off resulting in an irregular cycle. Medication is usually prescribed once a diagnosis has been confirmed. Once a thyroid problem is under management, the menstrual cycle usually goes back to being regular.


It is quite normal not to have a period while breastfeeding. The main hormone released for milk production is prolactin which halts ovulation. This means a lot of mothers will not have a period for several months or even until the child is weaned.  Do keep in mind, however, that you can still get pregnant during the breastfeeding phase because ovulation can still occur. It is best to use protection if you don’t want to get immediately pregnant again. Once a child is weaned the menstrual cycle should resume to normal within 6 to 8 weeks.

early peri-menopause

Menopause is the end to a woman’s fertility cycle. The production of eggs gradually slows down until it completely stops. Women usually begin menopause between the ages of 45 to 55. Sometimes hormonal imbalances will cause the onset of early menopause around the age of 40 but it is not very common.

Peace of mind

Experiencing late or missed periods can be worrying. Finding yourself asking why is my period late can lead to hasty conclusions. If you are truly concerned the best thing to do is make an appointment with a doctor. You will be able to find out what exactly is going on and plan a course of action to get things back to normal.

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