Maybe you were rushing one morning and forgot to take it. Maybe you didn’t refill your Rx before a trip and missed a week. Or maybe you’ve decided now’s the time to start trying for a baby.
Regardless of the reason, almost every woman who takes birth control pills skips or stops at some point. But it’s a little scary: You’ve been faithfully swallowing that same little pill every day, at the same time, for years. What’s happening in your body when you miss one, two, or more?
First, some background: Birth control pills work to prevent pregnancy by preventing ovulation, says Alyssa Dweck, M.D., a gynecologist in New York and assistant clinical professor at Mount Sinai School of Medicine. Most pills contain synthetic forms of two female hormones—estrogen and progestin. (One type, called a mini-pill, has progestin only.)
These synthetic hormones stabilize your natural hormones and prevent the peak of estrogen that would otherwise signal your body to ovulate, or release eggs from the ovaries to be fertilized. But skipping one pill and skipping several are two very different matters.
If You Miss One Pill 
Relax. “All of us have missed a pill or two—we’re only human!” says Sheryl Ross, M.D., OB/GYN at Providence …