Extended-cycle birth control pills: Is spotting common?

Yes. Spotting or bleeding between periods, also called breakthrough bleeding, is more likely with extended-cycle birth control pills than with traditional monthly pill packs. But breakthrough bleeding can happen with any birth control pill, especially during the first few months of use.

Birth control pills have hormones that stop periods. Monthly packs often include 21 hormone pills and seven inactive pills. Or these packs may contain 24 hormone pills and four inactive pills. Bleeding that’s like a period happens while taking the inactive pills. An extended-cycle pill pack contains hormone pills that you take for longer than a month. Another option called a continuous-cycle pack contains hormone pills that you take for a year or longer. Breakthrough bleeding is more likely with extended- or continuous-cycle birth control pills.

Breakthrough bleeding also can happen if you take monthly pill packs in a continuous way. That means skipping the inactive pills and starting right away on a new pack of hormone pills.

The cause of breakthrough bleeding with birth control pills isn’t always clear. It may simply take time for the body to adjust to the hormones in the pills. Or it may take time for the hormones to cause the lining of the uterus to become thinner. Without hormonal birth control, this lining builds up during each menstrual cycle. The vaginal bleeding of a period happens when the lining sheds.

You’re more likely to have breakthrough bleeding if you:

• Miss taking a pill.
• Start a new medicine or supplement that may interfere with birth control pills. Some antibiotics can have this effect. So can supplements such as St. John’s wort.
• Become ill with vomiting or diarrhea. This may affect the body’s ability to absorb the hormones in birth control pills.

Breakthrough bleeding with the use of extended- or continuous-cycle birth control pills usually happens less often over time. In the meantime:

• Keep taking the pills as directed. Breakthrough bleeding isn’t a sign that the pill isn’t working. If you stop taking it, you risk unplanned pregnancy.
• Track breakthrough bleeding in a calendar or diary. Typically, careful tracking offers reassurance that breakthrough bleeding is decreasing.
• Ask your healthcare professional about taking a short pill-free break. If you’ve taken active pills for at least 21 days, your provider may suggest that you stop for three days to allow bleeding that resembles a period and then take the pill again for at least 21 days.
• If you smoke, ask your healthcare professional to help you quit. Women who smoke are more likely to experience breakthrough bleeding than are women who don’t smoke.

If breakthrough bleeding becomes heavy or lasts more than seven days in a row, contact your healthcare professional. The bleeding may have a different cause such as an infection. Depending on the circumstances, your healthcare professional may recommend that you try a different birth control method.