Why Is My Period Late While I'm on Birth Control?

Missed periods can be a normal part of life. Some people have irregular menstrual cycles that can cause their periods to come and go. Pregnancy, breastfeeding, and menopause are other normal reasons that periods can stop.

Many people turn to hormonal birth control pills to prevent pregnancy and regulate their periods so they come at regular intervals. However, it is still possible to miss periods even on birth control.

There are several reasons periods may stop while on hormonal birth control, including changing forms of birth control, stress, diet changes, exercise, hormonal imbalances, and underlying health conditions.

In this article, we'll discuss what can cause missed periods on birth control, when it's normal and nothing to worry about, and when you should speak to your healthcare provider.

Reasons for a Missed Period on Birth Control

There can be a number of reasons that a person can miss a period while on hormonal birth control.

It is considered abnormal to go more than 90 days without a period unless a person is pregnant, going through menopause, or breastfeeding.

People may miss periods or they may stop getting a period entirely for a variety of reasons, including a change in birth control methods, stress, exercise, changes to diet, hormonal imbalances, and pregnancy.

Birth Control Changes

Changing forms of birth control, such as switching from the pill to the NuvaRing (eluryng), can result in skipped or missed periods as your body adjusts to the different hormone levels. This is normal.

You do not need to wait for your period to arrive to stop your old form of birth control and switch to a new one. Be sure to follow your healthcare provider's advice on when and how to switch. Your doctor can advise you on when to expect your period to return.

In some situations, you may need to use a backup birth control method (such as condoms) for up to a week after making the switch to protect against pregnancy.

There are also some forms of birth control that are known to cause periods to become lighter or to stop altogether over time. For example, the progestin-only pill (the minipill), hormonal intrauterine devices (IUDs, such Mirena, Liletta, and Kyleena), and the birth control implant Nexplanon can cause periods to become lighter. In some cases, people stop getting a period over time.

Your healthcare provider will tell you if you can expect a change in the frequency of your period when discussing your birth control options. But don't hesitate to ask follow-up questions if you notice changes that you weren't anticipating.

Stress

The part of the brain that controls the menstrual cycle is called the hypothalamus.

When the hypothalamus is working properly, it releases chemicals that cause the pituitary gland to stimulate other hormone-producing parts of the body. One body part the pituitary gland regulates is the ovaries, which release hormones called estrogen and progesterone. These hormones induce a period.

When the body is under stress, it makes a hormone called cortisol. This hormone can interfere with the interaction among the hypothalamus, the pituitary gland, and the ovaries.

This can cause a delay in periods, light periods, or no periods at all. Prolonged stress can lead to a period disappearing for a long time.

Stress is one of the many factors that can lead to hypothalamic amenorrhea—a medical term used to describe a condition in which periods stop because the hypothalamus is not releasing the hormones that induce a period.

High Intensity Exercise

Just as mental stress can cause missed periods, physical stress can also disrupt your menstrual cycle, even if you're on birth control.

High-intensity exercise can raise cortisol levels, which can interfere with the production of hormones that induce a period

If you're exercising to lose weight, that can also play a role in a missed period. Losing too much body fat can cause hormonal changes that stop ovulation, which in turn can cause periods to stop.

Missing a period due to exercise may be an indication you are not eating enough for your activity level. High-level athletes are at particular risk of missing a period due to excessive or overintense exercise and not eating enough for their energy needs.

Consulting a sports nutritionist or other nutrition counselor may be helpful in determining the calorie needs for your activity levels to maintain your energy levels and restore menstrual regularity.

Dietary Changes

An inadequate diet can cause you to miss a period.

If you don't eat an appropriate number of calories to sustain your activity level, your body has to use its energy stores to keep everything functioning.

In response, the body attempts to conserve energy, and one way it does so is by stopping ovulation. This is due to the body realizing it wouldn't be able to support a pregnancy. The reproductive system then shuts itself down in an act of self-preservation.

Sudden or extreme weight loss may cause periods to stop. People with eating disorders like anorexia or bulimia may find their periods stop.

Eating too much can also cause problems with periods. Gaining weight can cause the body to produce too much estrogen, which helps regulate the menstrual cycle.

Too much estrogen in the body can cause irregular periods, or cause them to stop entirely.

Abnormal Hormonal Balance

Hormonal imbalances in the body may cause periods to stop. This can be due to underlying conditions, such as:

• Polycystic ovary syndrome (PCOS): This condition causes the body to produce more of a type of hormone called androgen than is normal. This can cause sacs of fluids or cysts to grow in the ovary, which interferes with ovulation, the release of an egg from the ovaries. Most people with PCOS experience either irregular periods or their periods stop entirely (called amenorrhea).
• Fragile X-associated primary ovarian insufficiency (FXPOI). This condition causes the ovaries to stop functioning at a younger age than the usual age of menopause and, in turn, causes periods to stop. It is believed FXPOI is caused by a change to genes on the X chromosome.
• Thyroid problems. The thyroid gland, which is also regulated by the hypothalamus, can contribute to irregular periods, or periods stopping entirely. That's because the thyroid is responsible for the production of hormones that influence puberty and menstruation. Both an overactive thyroid (hyperthyroidism) or an underactive thyroid (hypothyroidism) can cause periods to be delayed or stop entirely.

Pregnancy

Being pregnant is the most common natural cause of periods stopping.

During the menstrual cycle, hormones cause the lining of the uterus to thicken. This makes a safe place for a fertilized egg to land and implant, becoming the start of a pregnancy.

A period happens when the uterus sheds this lining, because a fertilized egg did not implant here.

If the uterus is implanted with a fertilized egg, the body holds on to the lining of the uterus, which is why periods stop.

However, birth control works by stopping ovulation, so if you are on birth control, and taking it consistently as directed, it is unlikely a missed period while on birth control is due to pregnancy.

What to Do Next

In most circumstances, missing a period while on birth control is normal and nothing to worry about. If you've recently been under a lot of stress, exercising a lot, or have made significant dietary changes, you may want to make a lifestyle change (such as meditating to reduce stress or increasing your calorie intake) to get your cycle back to normal.

However, in some cases, missing a period on birth control can be due to pregnancy or be an indication of an underlying health problem. If your periods continue to lapse on birth control, or if you're having additional symptoms, such as fatigue or hair loss, it is important to speak with your healthcare provider about your concerns.

When to Talk to Your Doctor

You will need an additional evaluation if you have missed more than three periods in a row and you are not pregnant.

You should speak with your healthcare provider if you have any of the following symptoms:

• Difficulty with balance
• Difficulty with vision
• Difficulty with coordination
• Excessive growth of body hair
• Producing breast milk without having given birth
• Being older than 15 without having had a period

A Word From Verywell

Missing a period can be a normal part of life, and it may not be a cause for concern. Pregnancy, breastfeeding, and menopause are all natural causes for missing a period. Switching birth control may also cause periods to be delayed or skipped. Stress, diet, exercise, and hormonal imbalances can also cause periods to stop or be irregular.

In some cases, a missed period can be an indication of an underlying health problem. If you are concerned about lapses in your period, make an appointment to speak with your healthcare provider.