Many women worry when their period is late, but it could be due to a number of reasons, many of which are not considered particularly harmful. One of the most common reasons for a late period is a hormonal change, which may be due to pregnancy, breastfeeding, or certain types of contraception. Diet and exercise can also delay the period, as too much exercise and too little food can cause the body to temporarily stop menstruating. There are some conditions that may result in irregular periods, as well, such as thyroid disease, a pituitary tumor, or polycystic ovarian syndrome.
One of the most common reasons for a late period is pregnancy, which is why women who have had sexual intercourse in the months leading up to the delayed period should take a pregnancy test. If it is negative, and they have recently started a new type of hormonal birth control, it should be noted that this can cause a delayed period. Concerned women can read the packaging for their birth control, or ask a doctor about it to be sure this is the issue. Women who have recently had a baby and are breastfeeding should know that they will likely not get a period until they wean their child, so a delayed period is not typically a cause for concern in such cases.
If a period is delayed around the same time that a woman changes her diet or exercise routine, this may be a strong indicator of the likely cause. This is especially true in women trying to lose weight, as insufficient nutrients and excessive physical activity are a few possible causes for a late period. Even women who are done losing weight may notice this issue if their weight is too low for their height, as a healthy amount of body fat is usually necessary to menstruate. If the body is having trouble surviving on its current amount of fat, it will begin shutting down systems to save energy, and menstruation is often one of the first events that the body will stop. This is because it is not considered necessary for the body's survival, which is why gaining weight and eating sufficient nutrients should bring back menstruation.
There are also some medical conditions that are considered reasons for a late period, with polycystic ovarian syndrome being a common one. This is also usually referred to as PCOS, and is a hormone imbalance that can result in infertility, thinning hair, and irregular periods. On the other hand, some women develop a tumor on their pituitary gland that stimulates the body to make prolactin, resulting in delayed menstruation. Additionally, an issue with the thyroid gland is one of the possible reasons for a late period. Seeing a doctor can result in diagnosis and treatment of such conditions.