What Can Delay Your Period?

Here are reasons why your period is erratic or missing altogether—and what to do about it.

Medically reviewed by Cordelia Nwankwo, MD

If you have regular menstrual cycles, you may occasionally find that it's later than usual. While you might attribute the cause to having had an illness like the flu or a possible pregnancy, other factors can result in a late period.

Poor sleep, vigorous exercise, traveling across time zones, or weight changes are some of the reasons you may see a delay in having your period. Here's what you need to know, including how much of a delay is normal and when to see a healthcare provider.

Related: Two Periods in One Month: How Does This Happen?

1. Exercising Rigorously

You may see a delay in your periods from heavy exercise. Frequent vigorous exercise can be responsible for irregular periods and missed periods. You may also have irregular periods if you start exercising again after you haven't in a while.

Exercise puts physical stress on your body. This stress tells your brain to stop producing reproductive hormones.

One of those hormones is gonadotropin-releasing hormone (GnRH). This hormone is responsible for the timing of your periods. If your brain doesn't release or slowly releases GnRH, you can stop having periods—known as amenorrhea.



More About Ameorrhea

Amenorrhea is the absence of a period often caused by stress, weight loss, or frequent exercise. Other symptoms that may be associated with amenorrhea depend on the cause, and can include:

  • Changes in eyesight

  • Extra facial hair

  • Hair loss

  • Headache

  • Lack of breast development

  • Milky breast discharge



2. Weight Changes

Estrogen is produced mainly from adipose tissue (the tissue that makes up fat) after menopause. However, any extra fat can make estrogen at any time in a person's life. This means that when levels of fat in the body increase, estrogen levels also increase. As a result, the extra estrogen affects your menstrual cycle, leading to heavy periods and missed or irregular ones.

Too much estrogen for an extended period can also increase your risk of breast and endometrial cancer. However, going on the pill may help. Oral contraceptives have been associated with lowering the risk of developing endometrial cancer.

Additionally, if you lose weight too quickly, this may lead to irregular periods as well. Estrogen is necessary for building the uterine lining for a potential pregnancy during the menstrual cycle. When you lose a lot of weight, your body doesn't produce enough estrogen.

Related: 6 Self-Care Habits That Ease PMS Symptoms

3. Feeling Stressed Out

Feelings of stress can delay your period. Research has shown that people experiencing high stress levels were also experiencing irregular periods.

When stress affects the timing of a period, it can affect fertility. Those who are stressed out may have a more challenging time trying to conceive or have a healthy pregnancy.

Beyond irregular periods, stress can also affect your menstrual cycle in other ways. For example, individuals under high stress may experience more painful periods and changes in how long their cycles are.

Related: 10 Facts About Periods Everyone Should Know

4. Fluctuating Hormones

Issues with the thyroid—a gland in your neck—can affect the regularity of your period. Thyroid hormones are responsible for your body's energy control and affect many organs. When thyroid hormone levels are up or down, your body functioning can change—including your menstrual cycle functioning.

For those with an overactive thyroid gland—meaning they produce too much thyroid hormone—their periods tend to be shorter and occur more frequently. The opposite is true for those who don't make enough thyroid hormone and have an underactive thyroid. Their periods tend to be less frequent.

5. Exposure to Pesticides

Pesticides can be associated with irregular periods. One study's participants had been exposed to pesticides from working on farmland, living on it, or both.

Many had exposure to endocrine-disrupting chemical pesticides, a pesticide known to cause menstrual irregularities. Participants reported irregularities in their cycle length and the absence of their period for more than 90 days.

Some classes of chemicals can bind to receptors (molecules on the surface of a cell) for estrogen in the body. As a result, they can copy how estrogen functions in the body.

6. Breastfeeding

If you choose to breastfeed consistently, you may find that your period doesn't come back right away. This is known as lactational amenorrhea. Lactational amenorrhea happens after a person gives birth and increases the time it takes for a person to get pregnant again. For that reason, some individuals use it as a birth control method.



More About Lactational Amenorrhea

Using the lactational amenorrhea method (LAM) is meant to be temporary. If someone wants to use LAM as contraception, three conditions must be met to ensure that LAM is safe and effective:

  1. Amenorrhea after giving birth

  2. Breastfeeding full-time or nearly full-time (no more than 4-6 hours between feedings)

  3. Breastfeeding for 6 months after giving birth



However, if you are not using LAM and your period has not resumed after giving birth, consult a healthcare provider. They can help determine what might be causing a delay in your period.

7. Your Age

Your period may not get regular until your 20s. However, as you approach menopause, periods may become irregular again.

While you probably expect your period to become less frequent as you approach menopause, it can vary with its timing. For example, your period may stop for a few months and then return out of nowhere.

Related: How Your Period Changes As You Age

8. Sleeping Poorly

Getting less sleep can make you feel off, but subpar slumber patterns can throw off your cycle. What's more, sleep quality can get worse for individuals who experience premenstrual symptoms.

One study analyzed data from 579 participants concerning their menstrual cycles and how regularity was related to sleep duration, quality, and fatigue. The researchers found that heavier bleeding and irregular periods were related to:

  • Depression

  • Fatigue

  • Sleeping for a shorter time

  • Stress

  • Worse sleep

9. Traveling Across Time Zones

Estrogen levels change throughout your period. There is also an inverse relationship between estrogen and melatonin. Melatonin levels are down when estrogen levels are up, and vice versa.

Your brain produces melatonin to signal your body that it's time to go to bed. When you travel to another time zone, your body releases melatonin as if you're still at home, even if it's broad daylight in your new location.

10. Certain Health Conditions

You may also experience irregular periods if you have different health conditions. These conditions may include:

  • Eating disorders (including anorexia nervosa, bulimia nervosa, and binge eating disorder)

  • Pelvic inflammatory disease (PID)

  • Polycystic ovary syndrome (PCOS)

  • Primary ovarian insufficiency (POI)

  • Uncontrolled diabetes

You might experience irregular periods for different reasons depending on the health conditions. For example, you may have an infection of reproductive organs related to PID or hormonal imbalances if you have PCOS.



Looking for support?

If you or a loved one are coping with an eating disorder, contact the National Eating Disorders Association (NEDA) Helpline for support at 1-800-931-2237. For more mental health resources, see our National Helpline Database.

If this is an emergency call:



How Much Delay Is Normal?

It's normal for your cycle to be a couple of days off. Additionally, your menstrual cycle can still be considered regular if the timing is off for more or less than two to 20 days.

When To Contact a Healthcare Provider

A delayed period that's a few days off is generally nothing to worry about. However, you'll want to see a healthcare provider if:

  • Your period is consistently late

  • Your period is early by more than one week

  • You get irregular periods when you usually have regular ones

  • You miss more than three periods in a row or within a year

What Might Help Regulate Your Period?

Despite all the possible causes of irregular periods, some ways may help regulate your period, such as:

  • Getting enough quality sleep: Make sure that you get quality sleep. Quality sleep can look like getting enough sleep and having a consistent sleep schedule.

  • Maintaining a healthy weight: A healthy body weight, which will vary individually, can help with period regulation. Eating healthy foods and being physically active are the main ways to manage weight.

  • Relieving stress: Activities like reading, yoga, or doing anything you find enjoyable can help reduce stress.

  • Using hormonal birth control: Oral contraceptives typically contain estrogen and progestin. These hormones prevent the ovaries from releasing an egg. Other types of contraception, like intrauterine devices and implants, can also be used to regulate periods.

Related: 6 Things Your Period Can Reveal About Your Health

A Quick Review

Your period could be delayed by a few days, but that doesn't automatically mean it's irregular. However, many things can cause your period to be delayed or irregular. Some causes include health conditions like PID or PCOS, breastfeeding, weight changes, and hormone changes.

Hormonal birth control, getting enough sleep, and stress-reducing activities are a few potential ways to regulate your menstrual cycle. If you experience any issues with your menstrual cycle, consult a healthcare provider.

Frequently Asked Questions

What should I do if I have a late period?

See a healthcare provider if you're unsure why your period is late or if you think you may be pregnant. You should also consult a provider if your period is consistently late or if you're used to having regular periods but start having irregular ones.

Can your period be delayed by 10 days?

Yes. Additionally, your period could be delayed by up to 20 days without being considered irregular.

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