Why is My Period Late? 10 Common Reasons

Being late for your period can be scary, but this can occur for many reasons. Fortunately, there’s usually a simple explanation. Common causes for late or missed periods can range from hormonal changes to treatable medical conditions. If your period is late, it could be due to one of the reasons outlined below.

How Long Is It Normal for a Period to Be Late?

What a “normal” menstrual cycle is varies considerably from person to person, from one stage of life to the next, and for other reasons. The average cycle is 28 days, but anywhere from 21 to 35 days is common. If you go more than 35 days between periods, you should talk with your doctor about possible causes. They can help you figure out what’s going on with your cycle.

10 Reasons for a Late Period

If your period is late or you’ve missed one, don’t panic. In addition to pregnancy, there are many reasons why your period could be late. Here are the ten most common causes for a missed or late period other than pregnancy:

1. Change in fitness

Having a regular workout routine is a good idea for everybody. However, if you’ve recently increased the intensity of your workouts, you can experience exercise-associated amenorrhea (the absence of menstruation). When you burn too many calories, your body lacks the energy to keep all your systems running, which can lead to a hormonal imbalance that can throw off your menstrual cycle.

2. Weight Gain or Weight Loss

If you’ve lost or gained significant weight, you can experience hormonal imbalances that cause your period to come late or stop entirely. This is particularly true when your body mass index (BMI) changes rapidly.

3. Stress

When your stress levels increase, your brain tells your endocrine system to release hormones that switch on your fight-or-flight mode. These hormones suppress functions, including in your reproductive system, that aren’t necessary for escaping a threat. If you’re under significant stress, your body can remain in fight or flight mode, making you stop ovulating and causing you to miss periods.

4. Hormonal Birth Control

The pill is popular because it makes periods so regular. However, it can have the opposite effect, especially during the first few months of use. In addition, when you stop taking the pill, your cycle can take a few months to return to normal. You may stop getting your period altogether if you’re using a hormonal birth control method, such as an IUD, implant, or shot.

5. Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is a common medical condition that can cause irregular periods. An imbalance of reproductive hormones results in changes in the menstrual cycle and the development of ovarian cysts. Your doctor can prescribe treatment for PCOS.

6. Thyroid Disorders

Problems with the thyroid gland, like hyperthyroidism and hypothyroidism, are common and can affect your menstrual cycle. Hyperthyroidism is when your thyroid is overactive and produces too much of the hormone thyroxine. Hypothyroidism involves an underproduction of thyroid hormones. Both conditions are treatable.

7. Perimenopause

Perimenopause is the time when your body is transitioning into menopause. It tends to start when you’re in your 40s. Perimenopause typically lasts around four years but can persist as long as ten. Hormonal changes during this time can affect the menstrual cycle.

8. Chronic diseases

Various chronic diseases can cause late or missed periods. This includes conditions such as:

• Diabetes (particularly if not properly managed)
• Celiac disease (an autoimmune disease that affects the digestive system)
• Asherman’s syndrome (a rare condition that causes uterine adhesions)
• Cushing syndrome (a condition where the body overproduces the steroid cortisol)
• Congenital adrenal hyperplasia (a hereditary problem with the adrenal glands)

9. Youth

It’s common for the menstrual cycle to fluctuate in adolescence. Often, it takes a few years to settle into a standard rhythm. Periods typically become more regular in the late teens and early 20s.

10. Primary Ovarian Insufficiency (POI)

Primary ovarian insufficiency (POI) is where the ovaries stop functioning normally in people younger than 40. It can cause eggs to be released unpredictably. POI may also cause the underproduction of hormones.

When to Suspect Pregnancy

If there’s a chance you may be pregnant, you’ve missed a period, and your cycle is usually normal, it may be time to take a pregnancy test. Your periods will stop when your body starts producing the pregnancy hormone human chorionic gonadotropin (hCG). It’s recommended that you take a pregnancy test a week after your period is supposed to start. If your periods are typically irregular, it can be harder to determine the best time to take a pregnancy test. You may want to take a few tests over several weeks to make sure. This is also a good time to contact your Baptist Health provider.

Late Period? Missed Period? Talk to a Baptist Health Professional.

There are many reasons for late or missed periods. If you haven’t had a period in more than 40 days, you should make an appointment with your Baptist Health provider.