Why is my Period Late?

For most women, their menstrual cycle is rarely the expected 28 days long. A little variation is normal, with the average cycle ranging anywhere from 21 to 35 days. And if your period is a day or two late, there is no need to panic.

What is a period classified as ‘late’?

Doctors advise that if your cycle has lasted more than 35 days, or if your cycle is usually regular but your period is more than three days late, menstruation is considered delayed.

A late period may cause you to panic – particularly as delayed menstruation is often associated with pregnancy. However, a late period can be caused by a number of different things.

Why is my period late?

Here are 7 reasons – other than pregnancy – why your period may be late and what to do if it happens.

1. Stress

Stress is a common reason for a late period. When we are under a lot of stress in our daily lives, it can affect us physically as well as mentally, with delayed menstruation being one of the symptoms.

High levels of stress, caused by things such as work pressures, major life events, or the death of a loved one, can affect the balance of our hormones and interfere with the menstrual cycle.

If you think stress is causing you to experience physical symptoms, always talk to your doctor.

2. Polycystic ovary syndrome (PCOS)

PCOS is a common disorder that causes a hormonal imbalance. Many women with PCOS have irregular or infrequent periods as it affects the body’s ability to ovulate (if you don’t ovulate, you don’t usually have a period).

PCOS also causes excess androgen (male hormone) levels, and/or polycystic ovaries. It can also cause acne, excess hair on the face or body, and weight gain.

If you have been diagnosed with PCOS, your doctor will discuss medication and lifestyle changes that may help to manage the symptoms.

3. Extreme weight loss or exercise

If you suddenly lose a lot of weight, or you put your body through extreme amounts of exercise, it can cause your periods to stop temporarily. This is a condition called secondary amenorrhea.

This is essentially your body’s way of telling you that it isn’t getting enough calories to support a pregnancy. Secondary amenorrhea can also be caused by an eating disorder or by following an extremely low-calorie diet.

4. Thyroid conditions

The thyroid is a gland at the base of the neck that releases hormones that can affect your period. Problems with the thyroid are common in women and can cause late and irregular periods.

The thyroid can be overactive (hyperthyroidism) or underactive (hypothyroidism), both of which can cause a late period.

5. Birth control

Hormonal birth control contains the hormones which can work to prevent pregnancy - progestin or progestin and estrogen combined.

Taking hormonal contraceptives can cause a withdrawal bleeding, which is a bleed during the week you don’t take the birth control. However, if you take hormonal contraceptives continuously, you may have no period at all.

Missing a period while taking hormonal contraceptives is fine but always discuss it with your doctor first.

6. Young age

If you are young, and haven’t been menstruating for long, it can take a while to establish a monthly cycle. This is because hormonal system that regulates the menstrual cycle and ovulation can take a few years to mature.

If you reach your late teens and your period is still irregular, or painful or heavy, speak to your doctor as there may be another cause.

7. Perimenopause

Perimenopause is the stage before menopause, and it can begin anywhere in your 40s or 50s. It can last for several years and during this time, your menstrual cycle may be interrupted.

Perimenopause can also cause lots of other symptoms, such as mood swings, insomnia, hot flushes, cramping, and vaginal dryness.

Delayed menstruation during perimenopause is common, but if your periods are much heavier or closer together, tell you your doctor so they can rule out other causes.

Keep track of your periods

If your period is late by a couple of days, it isn’t usually a cause for concern. Sometimes though, it can be a sign of a medical condition. If your period is regularly late, then talk to your doctor.

Using an app is an easy way to track your periods. You will be able to see straight away if something changes and the information will be there for your doctor to easily see.