Irregular Periods: Why Is My Period Late?

Irregular periods aren’t always a sign of a problem. We break down what you should know about how to identify irregular periods, what causes them and when to see a doctor.

During a normal menstrual cycle, an egg is released from one of your ovaries during ovulation. If the egg is not fertilized by a sperm, then changing hormone levels send your body a signal to shed the blood and tissues that line your uterus. This bleeding typically lasts about five days. Then, the monthly cycle repeats itself.

But some women have what is called abnormal uterine bleeding — another term for irregular periods — which can happen for a variety of reasons, from stress and lifestyle factors, to more serious underlying medical conditions.

An irregular period is when the length of your menstrual cycle unexpectedly falls outside of your regular range. Irregular periods can include abnormal uterine bleeding, such as:

• Bleeding or spotting between periods
• Bleeding after sexual intercourse
• Heavy bleeding during your period
• Menstrual bleeding that lasts longer than normal
• Bleeding after you’ve reached menopause

There are a number of reasons why you may have an irregular, missed or late period, ranging from stress to more serious medical conditions.

Common causes of irregular periods include:

• Uncontrolled diabetes: If you have uncontrolled diabetes, you may have irregular periods because the interaction between your blood sugar levels and hormones can disrupt your menstrual cycle.
• Eating disorders: If you have an eating disorder, such as anorexia or bulimia, you may have irregular or missed periods. This is because your body is not producing and circulating enough hormones to control your menstrual cycle.
• Hyperprolactinemia: Women who have too much of a protein hormone called prolactin in their blood can have irregular periods.
• Medications: Certain medications, including anti-epileptics and antipsychotics, can cause irregular periods.
• Polycystic ovary syndrome: PCOS is caused by imbalanced sex hormones, which can disrupt regular menstruation.
• Stress: Stress hormones can affect menstruation and prolonged stress can cause your period to be delayed or for you to skip it entirely.

If you experience any of the following symptoms, it may be time to talk to your doctor:

• You haven’t had a period for 90 days
• Your period suddenly becomes irregular
• You have a period more often than every 21 days
• You have a period less often than every 35 days
• Your period lasts for more than a week
• Your period becomes unusually heavy
• You bleed between periods
• Your periods are extremely painful