6 Reasons Why You Missed Your Period While on Birth Control

6 Reasons Why You Missed Your Period While on Birth Control

Image: iStock


Birth control pills are an effective way to prevent conception. Since periods are an indication of no pregnancy, you may have expected them when on birth control. But, that is not how oral contraceptive pills work. As a matter of fact, amenorrhea or absence of periods is common among women taking birth control pills (1).

Oral contraceptive pills alter the hormonal levels in the body to prevent conception. These changes have an impact even on the menstrual hormones, leading to a delayed period. Once birth control is stopped, your periods will return to their normal cycle.

Sometimes, there could be other reasons why you may have missed a period on birth control, too. So read on to know why you may have no period with birth control and how birth control pills affect your menstrual cycle.

Does Missing A Period Mean You Are Pregnant?

Although you may think you are pregnant when you have a delayed period, it is not always the case. Lack of menses is common in those with ovarian disorders or eating disorders. Periods may also get delayed during traveling and among breastfeeding women (2). Nevertheless, if you have been sexually active and doubt you could have conceived, a pregnancy test is the only way to confirm the absence of periods due to pregnancy.

What Can Cause A Missed Period On Birth Control?

There are several contributing factors to a missed period. Identifying the source could put your periods right back on track.

  1. Stress: Increased stress may cause irregular and sometimes even stoppage of periods. Stress has an unfavorable impact on the ovaries. The hypothalamus controls the functions of the ovaries via the pituitary gland. Stress may impair the functions of the hypothalamus. This dysregulation could tilt your body’s hormonal levels towards an irregular period (3).
  1. Dietary changes: A sudden change in the diet could affect the menstrual cycle. Anorexia and bulimia could reduce the production of certain female hormones in the body. This imbalance, in turn, may result in delayed menstrual periods or the absence of menstruation(4).
  1. Exercise: Intense exercises may accompany irregular periods either due to the conscious and decreased calorie intake that may follow or due to over-expenditure of energy. Your body may enter starvation mode and deem it necessary to keep the vital organs well-functioning. As periods may not be a priority, they could postpone leading to irregular periods or amenorrhea(5). This may not occur in women who have a few intense workouts in a week or a month and rather be common in athletes.
  1. Continuous use of birth control: A birth control pill prevents your body from preparing pregnancy- and menstruation related-hormones. If you have been on birth control pills or have been using other birth control methods, it may take your body a few weeks or even months to return to the usual cycle. Abrupt stoppage of pills may also lead to delayed periods or post-pill amenorrhea 6(7).
  1. Imbalance in hormones: Sometimes, delayed periods could be due to underlying health problems, such as polycystic ovary syndrome (PCOS). Hormonal problems, common in women with PCOS, may cause improper or no production of eggs. The development of cysts is also seen in PCOS. Ovary-related illnesses like these could be a causative factor for amenorrhea or irregular periods(8).
  1. Pregnancy: Most contraceptive pills are 99% effective. But there could be a one percent chance of becoming pregnant. This is more likely to happen if you’ve missed a pill in the dosage (9). Breast tenderness, nausea, and frequent urination are a few pregnancy symptoms that you may notice early (10).

How Do Birth Control Pills Affect Periods?

Birth control pills act on the hormones that cause pregnancy, that is, estrogen and progesterone. In a one-month pack of pills, usually, there are three weeks of hormonal pills and one week’s worth of placebo pills. The active pills could be a combination birth control pill (estrogen and progestin) or just progestin (for those at risk of blood clots). While the hormone birth control pills prevent your eggs from being released, the inactive pills are a simple reminder to take the pills every day (1)(11).

The hormonal contraceptives act by any of these following mechanisms (12).

  • By thickening the cervical mucus, preventing the sperm from entering the uterus
  • By preventing the release of eggs (reduced ovulation)
  • By thinning the cervical lining of the uterus, making the attachment of a fertilized egg difficult

Since the very functioning of the uterus and related hormones are disrupted due to pill intake, menses could get postponed. It could lead to missed or no periods when on birth control. In many women, it may take some time for the body to adjust its menstrual routine even after discontinuation of pills. Regular periods return eventually after the stoppage of oral contraceptive pills.

How To Keep Your Menstrual Cycle On Track?

Keep a note of the day you stopped taking your pills. It may take your body two to four weeks after termination of the pills to get back on track. Furthermore, periods could be irregular for three months or until the body’s hormone levels return to normal entirely (13).

The first period you experience after the stoppage of the pill is considered withdrawal bleeding. You can consider the periods following it to be your regular monthly periods. You can track these by using the standard 21-35 days cycle (14).

If you have missed your period on birth control, it could be because your body is still getting used to the absence of hormonal intervention. Nevertheless, if you are worried, you may pay a visit to your healthcare provider. Medical advice would lean on identifying the underlying reason and putting your cycle back on track.


MomJunction's articles are written after analyzing the research works of expert authors and institutions. Our references consist of resources established by authorities in their respective fields. You can learn more about the authenticity of the information we present in our editorial policy.
  1. Birth Control: The Pill.
  2. Missed or Irregular Periods.
  3. Can Stress Cause You To Skip A Period?
  4. Irregular Periods: Why Is My Period Late?
  5. Is It Normal To Lose Your Period Because Of Exercise?
  6. Hillard P. A.; Menstrual Suppression: Current Perspectives.
  7. Wright K. P. and Johnson J. V.; Evaluation Of Extended And Continuous Use Oral Contraceptives.
  8. Polycystic ovary syndrome.
  9. How Effective Is Contraception At Preventing Pregnancy?
  10. Pregnancy: Am I Pregnant?
  11. Noncontraceptive Benefits of Birth Control Pills.
  12. Combined Pill.
  13. When Will My Period Come Back After Stop Taking The Pill?
  14. Normal Menstruation.