Breakthrough bleeding refers to any unscheduled bleeding during your menstrual cycle. It’s typically a small amount of spotting, though some experience heavier bleeding.

Breakthrough bleeding is a common side effect of hormonal or long-acting birth control. It’s especially common in the first 3 to 6 months and often decreases over time.

While it can be inconvenient, it’s usually not a cause for concern.

In a typical menstrual cycle, estrogen and progesterone thicken the endometrium (uterine lining) to prepare for potential pregnancy.

These hormone levels drop if pregnancy does not occur. The uterine lining sheds, resulting in menstruation or period-like “withdrawal bleeding.”

If you’re taking hormonal birth control, the dosage of specific hormones can impact the way your uterine lining responds.

Increased blood flow to the uterus, for example, may trigger unexpected or “breakthrough” bleeding until your body adjusts to this change in hormone levels.

Breakthrough bleeding can happen with any form of hormonal or long-acting birth control. This includes the:

However, it’s more common with:

You’re more likely to develop breakthrough bleeding if you miss a dose or fall behind your contraceptive schedule. This may look like:

  • forgetting to take your pill within the same three-hour window each day
  • incorrectly applying a new skin patch
  • inserting a new vaginal ring a day later than expected
  • missing your Depo-Provera appointment

If you take the pill, the following can also increase your risk of breakthrough bleeding:

  • smoking traditional cigarettes, vaping fluids with nicotine, or using other tobacco products
  • persistent vomiting or diarrhea
  • taking certain drugs, including some antiretrovirals for HIV and some epilepsy medications
  • taking certain supplements, such as St. John’s wort

If you’re currently taking oral contraceptives or want to make the switch, you might benefit from a:

  • combination pill with a higher dose of synthetic estrogen
  • progestin-only minipill with norethindrone acetate
  • progestin-only minipill with drospirenone

If you have the implant and are experiencing unusual bleeding, talk with a healthcare professional about whether tamoxifen could help manage it.

Breakthrough bleeding usually isn’t a cause for concern, especially occasional spotting or light bleeding. Consistent or heavy bleeding may be a sign of an underlying condition that requires treatment.

Consult with a healthcare professional if you have:

  • bleeding that lasts more than 7 consecutive days
  • bleeding that soaks through a pad, tampon, or other menstrual product within 2 hours
  • severe abdominal pain
  • fever

Take note of how much you bleed, when it happens, and how long it lasts. This information can provide important clues to help a healthcare professional determine the cause of your bleeding.

Be sure to note if birth control use has been inconsistent or if you have symptoms of pregnancy. Your healthcare professional can perform a pregnancy test to rule it out or provide you with a clear answer.

Breakthrough bleeding with hormonal or long-acting birth control is common, especially in the first few months.

It doesn’t necessarily mean your birth control is ineffective. Pregnancy is unlikely if you’re consistently using your birth control as prescribed.

If bleeding persists or is accompanied by symptoms that interfere with your daily activities, it’s a good idea to make an appointment with a healthcare professional.

They can help determine the underlying cause and answer any questions you have about your choice of contraception.