What Are the Causes of Breakthrough Bleeding While on Birth Control Pills?


Breakthrough bleeding is when menstrual bleeding occurs between periods. It can be light spotting or just as heavy as your typical period. This can happen when taking an oral contraceptive. This can become a very frustrating problem for women on the pill, because one of the reasons they may be taking it in the first place is to regulate their cycles. There are several reasons why breakthrough bleeding may occur. Finding the cause of the problem is the first step to finding a solution.

Patient Behavior

The most common cause of breakthrough bleeding is the patient's failure to accurately follow the instructions for the medication. The directions should be read thoroughly and any questions should be discussed with the patient's gynecologist before use. The most important thing to remember is to not skip doses. It should be taken at the same time every day. The cycle is so sensitive and exact that the pill should be taken within a 15-minute time frame every day. Find a way to remember to take your pill at the same time every day. This could mean setting an alarm on your cell phone to remind you.

Estrogen and Progestin

The formula for oral contraceptives is a combination of the two hormones estrogen and progestin. The estrogen causes the lining of the uterus to grow while progesterone stabilizes it. Doctors usually begin by prescribing an oral contraceptive that has the least amount of these hormones. These pills are known as "low dose" and are effective in a lot of women. Most of the time, only a small dose of the hormones is enough to prevent pregnancy. However, for some women the low-dose pill doesn't contain enough estrogen to maintain the stability of the endometrium, and breakthrough bleeding occurs. This can usually be remedied by switching to an oral contraceptive with more estrogen or a higher combination of both hormones.

Type of Progestin

Not only may breakthrough bleeding occur due to the amounts of estrogen and progestin, it may also depend on the type of progestin. There are several different types of progestin that are used in different oral contraceptives. The two classifications are gonanes and estranges, and each category contains a variety of different types. Switching to a pill with a different type of progestin may be enough to stop breakthrough bleeding.

Cycle Length

You have probably seen the commercials and heard about the oral contraceptive that allows you to only get your period four times a year. While this may sound great, it seems that breakthrough bleeding occurs more often with this kind of pill and other extended cycle pills than with the 28-day regimen pills. Switching from longer cycle pill to a 28-day pill may reduce breakthrough bleeding, however actual menstruation will occur more frequently.

Other Factors

Other factors may contribute to breakthrough bleeding. Smokers tend to have more problems. Also, several sexually transmitted diseases can contribute to bleeding between cycles. Sometimes, certain prescription medications may be reacting adversely with the pill. A patient who has had irregular bleeding for several months, and other causes have been ruled out, should be tested for cervical and endometrial cancer or benign growths.