Here's What to Do if You Miss a Birth Control Pill, According to Doctors

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It's inevitable: Anyone who uses oral contraceptives has forgotten to take a birth control pill at one point in time. (If you haven't, kudos to you.) Some days, the hustle and bustle of life takes over, and popping a tablet from that little pack of pills simply slips your mind. Anyone who has experienced this common memory lapse also knows what it feels like the moment you remember that you missed a pill—aka a heart-dropping realization that usually results in some swear words. But what should you do once you realize that you're behind on your birth control pills?

To help answer the common questions that arise when we forget to take our birth control pills, HelloGiggles spoke to two women's health experts: New York-based gynecologist Dr. Alyssa Dweck, M.S., M.D., F.A.C.O.G., and Dr. Sophia Yen, M.D., M.P.H., cofounder and CEO of Pandia Health.

So, how do birth control pills work?

In order to understand what happens if you miss a birth control pill, you first need to understand how birth control pills work. First, there are several types of oral contraceptives. The most common type is combination pills, which contain both estrogen and progestin, aka the synthetic version of progesterone, and are used by women who either want to combat acne, prevent pregnancy, or reduce menstrual pain or migraines. And then there are minipills (progestin-only pills), which are taken by women who are breastfeeding (because estrogen can reduce their milk supply) or women with specific health conditions, like a history of blood clots or liver disease.

When you take either combination or progestin-only pills, this changes the natural hormone levels your body already produces on its own. Higher levels of these hormones prevent women from ovulating, thicken the cervical mucus to stop sperm from entering the uterus, and thin the uterus lining so that an egg is less likely to attach and get fertilized by sperm. "The way combination birth control pills work is that they keep your hormones up," Dr. Yen tells HelloGiggles. During the first ten weeks of pregnancy, hormone levels double every two days, so the hormones in birth control mimic this rise. "This tricks your body into thinking that you’re pregnant so that it doesn’t want to release an egg and doesn’t grow on the lining of your uterus."

However, 40% of women who take the minipill will continue to ovulate, which is the key difference from the combination pill. The combination pill takes a full week to become effective for pregnancy prevention, with one exception: If you start the pill five days after the first day of your period, it will be effective that same day. On the other hand, the minipill is effective just 48 hours after entering your system.

Do you ovulate on birth control?

Women typically ovulate, aka release an egg from the ovary, around 12 to 16 days before their period, according to the American Pregnancy Association. The egg will live for about 12 to 24 hours after being released and can be fertilized during the time period. As Dr. Yen noted above, taking birth control pills increases the amount of estrogen and progestin in your body so that you do not ovulate and therefore cannot get pregnant.

"Because combination birth control pills prevent ovulation, this means there is no chance of fertilization and pregnancy," Dr. Dweck explains. "However, if you miss the pill for more than two doses, the typical hormone signals from the pill that tell the ovaries not to ovulate may be interrupted, and ovulation can occur."

What happens if you miss a birth control pill?

If you only miss one birth control pill, the side effects are minimal. "There's no issue with missing one pill other than possible irregular spotting, which is just a nuisance and no cause for concern," Dr. Dweck says. So, if you miss one pill and you're sexually active, you don't need to panic, as your chance of getting pregnant is minimal. However, if you miss two or more pills—meaning you might ovulate—Dr. Dweck says, "You should use a backup method of birth control until you’re back on track (when you've started a new birth control pack)," especially since birth control is only 99% effective if you take the pill at the exact same time every day.

What to do if you miss a birth control pill:

The answer depends on how many pills you've missed. If you only miss one pill, both Dr. Yen and Dr. Dweck suggest you take it as soon as you remember. This most likely means you'll take the pill at a different time than you normally do. This shouldn't affect your body—or the effectiveness of the pill—much at all (except for possible spotting, which is brought on by the doubling of the hormones).

If you missed more than two pills, do not take all of the missed pills in one gulp. Instead, Dr. Yen says to "take two right away and two the next day to catch up." If you missed five or more days of your birth control pills, she recommends that you start from scratch and open a new pack of pills. However, if you're unsure how to proceed after missing multiple pills or want further medical instruction, reach out to your OB-GYN, since every body is different.