6 Reasons Why You Missed Your Period On Birth Control

Since periods indicate no conception, it is natural to expect them after taking birth control pills. But what if you missed a period on birth control? Does it indicate that the oral contraceptive pill wasn’t effective? Not always, since amenorrhea or lack of periods is a common effect of birth control pills (1).

The lack of periods usually occurs because oral contraceptive pills work by altering the body’s hormonal levels. Mostly, the delayed period is because of its effect on menstrual hormones. Your periods may return once you stop the intake of oral pills. But, sometimes, a few other factors may lead to the absence of periods.

Read on to know more about how oral contraceptives act on your menstrual cycle and cause a delay. We have also written about a few other factors contributing to amenorrhea.

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 first 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).

2. 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).

3. 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.

4. 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).

5. 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).

6. 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, or if you have been taking it at different times, taking other medications, or been sick (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 (stopped 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).

References

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Reviewer

Dr. Karla S. Sanchez-BanosMD

 

Dr. Karla S. Sanchez-Banos is a board-licensed Ob/Gyn in Mexico, specializing in Adolescent Gynecology. She is also trained in Gynecological Endocrinology, granted by AMEGIN (Gynecological Endocrinology Mexican Association).

Read full bio of Dr. Karla S. Sanchez-Banos