Here’s Why You Missed Your Period While on Birth Control

Medically reviewed by Debra Rose Wilson, PhD, MSN, RN, IBCLC, AHN-BC, CHT on April 18, 2017Written by Ashley Marcin

Missing your period while on birth control

Taking birth control pills is an effective way to prevent pregnancy and treat many medical conditions. Since the pill works by introducing different hormones into your system, it can affect your menstrual cycle. Some women may have lighter bleeding, and others may skip their periods entirely. An abnormal lapse in monthly menstruation is called amenorrhea. There are other reasons why you might miss your period while on birth control pills, though.

If you take the pill, here are some reasons why you might have missed your period.

1. Stress

Excessive stress can affect your mind and body. Too much stress can impair the function of your hypothalamus. This is the part of your brain that controls hormone regulation. Discovering the source of your stress and managing your stress levels may help your period start back up again.

Read more: 10 simple ways to relieve stress »

2. Dietary changes

Changing your eating habits and losing weight too quickly can interrupt your menstrual cycles. Low body weight, especially if you’re 10 percent underweight or more, may also stop your body from ovulating and keeping regular cycles. Women with eating disorders such as anorexia and bulimia are particularly at risk.

3. Exercise

Too much exercise can also disrupt hormone levels and stop your period. Of course, exercise in moderation is a great way to stay healthy and fit. More strenuous training, like the kind performed by professional athletes and dancers, is usually the cause. Some recreational athletes who engage in long-distance events may also experience this.

4. Continuous birth control

Some women choose to take continuous birth control pills. Popular brand names include Seasonale, Seasonique, and Yaz. If you use this type of pill, you’ll continuously take all active pills for three months, followed by a week of inactive pills. Although you may have spotting between months, your period may only come four times per year during the weeks with inactive pills. It’s not uncommon for people on injectable birth control to also experience a lack of periods.

Does missing a period mean you’re pregnant?

While rare, it’s still possible to become pregnant while taking birth control correctly. If you’re sexually active and have noticed only spotting or have skipped your period entirely, you should contact your doctor to rule out pregnancy. Checking to see if you are pregnant is especially important if you’ve missed or skipped doses of your medication. You could do a home pregnancy test, but false positives and false negatives can happen. If you do have a positive pregnancy test, it’s essential to begin prenatal vitamins (with folic acid) and doctor’s visits immediately.

Early symptoms of pregnancy include:

These signs may develop as soon as a week after your missed period. Your menstrual cycle is hormonally regulated while on the pill, and you should get some type of bleeding about every 28 days. Use this information to keep track of when your period is late so you can report back to your doctor with any concerns.

Most birth control failures happen when you have missed two or more doses of pills in a row. Pregnancy can also happen if you are late by even a day or two for your injectable birth control.

Learn more: When you should take a pregnancy test »

How do birth control pills work?

There are two different types of birth control pills. The first combines man-made forms of the female hormones estrogen and progesterone. The second is a progestin-only minipill.

Although many women take birth control pills to prevent pregnancy, the pills can also be used to help with menstrual issues, such as severe cramps and heavy bleeding. Birth control can even be used to clear up skin problems, such as acne.

The pill works in a few different ways to help prevent pregnancy. It can:

  • prevent ovulation
  • thicken cervical mucus so sperm can’t easily reach the egg
  • thin the uterine lining to prevent the fertilized egg from implanting

Most birth control pills come in packages containing 28 pills each. The first three weeks’ worth, or 21 pills, contain the hormones. The last week’s worth, or seven pills, contain placebos. Taking your pill at the same time each day helps maintain stable hormone levels in your body. The placebos help you remember to take a pill every day, regardless of the time of the month.

The effectiveness of birth control pills is greatly increased with consistent use. In other words, it can be 99 percent effective if you remember to take them at the same time each day and never miss a pill. This also requires that you start your new pack on time each month. If you are ill with diarrhea or vomiting, it can also influence effectiveness. Some medications interfere with the effectiveness of hormonal birth control, as well.

When you miss or skip doses, you may have spotting or irregular bleeding. Since many women end up missing or skipping doses of birth control pills, the overall effectiveness is about 91 to 99 percent.

How to keep your menstrual cycle on track

If you miss your period while on the pill and you haven’t missed any doses, pregnancy isn’t likely. Instead, the hormones in the pill are likely the cause. If you miss a second period and haven’t missed any doses, pregnancy is still unlikely. At this point though, if you’re sexually active, it’s still worth taking a pregnancy test or calling your doctor.

Your doctor can help you address any other factors that may be at play. After you’ve pinpointed the cause, you should be able to get your period back on a regular cycle. You may be able to do this in a number of ways:

  • Make sure you take time to relieve stress. Try breathing techniques, yoga, restorative walks, and even journaling to get at the root of your stress.
  • Eat a healthy diet and work to keep your weight in a normal range. If you suspect you have an eating disorder, tell a friend or your doctor so they can point you to the resources you need to get help.
  • Keep up with regular exercise. Your activity level may seem manageable to you, but see if stepping back a bit helps your regular bleeding resume.

Takeaway

Missing your period while taking birth control pills with regularity is usually no reason for alarm. Contact your doctor with your concerns or take a home pregnancy test to ease your mind. Many women find that their periods return with simple lifestyle changes. When you’re on birth control pills, light bleeding or a missed period may be normal.

Birth control pills are incredibly effective at preventing pregnancy with perfect use. Your doctor may be able to prescribe a pill that will work better for your body, depending on your reasons for taking it and any adverse symptoms you have. Talk to your doctor about any issues so you can work together to find the right fit.

No matter what pill you choose, it’s important to remember that birth control pills don’t protect against sexually transmitted diseases. Use a backup method like condoms or dental dams to practice safer sex.

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