8 Potential Causes Of Irregular Periods

Missing a period can be worrying. When is this normal and when is it not? How long can you let things be? What causes irregular periods and when should you start investigating? If you’ve been trying to figure these out, we may have some answers for you. But, first, let’s start with how exactly your menstrual system works.

Your Menstrual Cycle: How It Works

Your periods are governed by an intricate hormonal system that produces hormones in a certain order each month to prepare your body for pregnancy. When this system is functioning properly, the uterus sheds its lining at the end of the cycle, resulting in a menstrual period when there’s no pregnancy. Hormones produced by the hypothalamus, the area of the brain that helps in regulating the pituitary gland, the pituitary gland, which produces follicle-stimulating hormone and luteinizing hormone, and the ovaries, which produce the hormones progesterone and estrogen, play an important role here. Hormones like prolactin and those produced by the thyroid gland can affect your menstrual cycle too.1


How Often Should You Expect A Period And For How Long?

On an average, most women have their periods every 28 days and it lasts between 4 and 7 days. There can, however, be a wide variation from this, with some women having a period every 21 days and some every 35 days. This may be normal for them.2

It’s also not unusual to have a shorter or longer menstrual cycle or heavier or lighter periods for a few years before menopause or after puberty when your hormones may be slightly off balance.3 However, if you haven’t had your period for more than three months, you should speak to a doctor even if you’ve just undergone puberty as it could be indicative of some underlying issues.4


Let’s take a look at some factors that could be making your periods irregular.

Causes Of Irregular Periods

1. Lifestyle Factors

Some lifestyle factors can result in hormonal imbalance and affect your menstrual cycle, thereby causing irregular periods.


Excessive exercise as is usual for competitive athletes, especially in sports where they have to maintain a low body weight, may have an effect on the hypothalamus.

Poor nutrition and extreme weight loss as is seen in women with eating disorders can also influence the hypothalamus.


Stress and mental disorders like obsessive-compulsive disorder or depression may cause the hypothalamus to malfunction too.5

Obesity can cause your body to produce extra estrogen which may throw off your menstrual cycle too. If your body mass index (BMI) is 30 or more and your periods are affected, you may need to lose weight.6


2. Thyroid Disorders

The thyroid gland produces hormones which regulate your metabolism. And though it’s rare, thyroid disorders involving an overactive thyroid or underactive thyroid can also result in irregular periods.7

3. Polycystic Ovary Syndrome (PCOS)

PCOS is a condition that is characterized by hormonal imbalance and can cause irregular periods. Women with PCOS may have higher levels of testosterone, the male hormone. They may also not ovulate as often as is normal.8


4. Contraception

Some kinds of contraception like the progestogen-only pill or the intrauterine system (IUS) may stop your periods. But when you stop using them, your periods usually return. It’s also not unusual to miss a period once in a while when you’re on the pill and this should not cause you concern.9

5. Medical Conditions

Some chronic conditions like uncontrolled diabetes and heart disease can affect your periods.10


6. Medications

Certain medications, for instance, some antiepileptics and antipsychotics, can give you irregular periods.

7. Hyperprolactinemia

Hyperprolactinemia, a condition which is characterized by an abnormally high level of prolactin, a protein hormone, in the blood can throw your menstrual cycle off.

8. Tumors

Ovarian, adrenal, or pituitary gland tumors can affect your menstrual cycle.11

What Causes Prolonged Or Heavy Bleeding?

If you need to change your menstrual product every one or two hours, your menstrual flow is considered excessive especially if your period lasts for more than seven days.12 Some factors that could cause this are:

  • Uterine fibroids (growths in the womb) or polyps
  • Bleeding disorders like leukemia or von Willebrand disease
  • Hypothyroidism (an underactive thyroid)
  • Liver disease13
  • Endometriosis, a condition where the tissue that forms the lining of your womb grows outside it – for instance in the ovaries, fallopian tubes, or bladder14
  • Pelvic inflammatory disease (PID), which is an infection in the fallopian tubes, womb, or ovaries.15

What Causes Pain During Menstruation?

Things like smoking, depression, endometriosis, chronic uterine infections, and heavy menstrual flow can result in excessive pain during menstruation.16

What Next?

Treatment of menstrual irregularities may involve taking care of the underlying health issue. Keep track of how often you get your periods and of symptoms that accompany them. If you haven’t had a period in three months, a visit to your OB/GYN is called for. Your doctor will then help you decide the next course of action, be it recommending lifestyle changes or prescribing contraceptives or other medication.You may also be asked to get a pregnancy test or ultrasound to rule out a pregnancy if you’ve been sexually active.17