How frequently can you take Plan B? Whether you’ve taken the morning after pill twice in one week or multiple times in a month, there is no research that using Plan B too often brings long-term negative effects, such as infertility. However, you should be aware that overuse of Plan B does increase the chance you’ll experience side effects.

Using Plan B affects your ovulation stage, changing your menstrual cycle. Frequent use will result in a more irregular cycle. If you experience heavy bleeding after taking Plan B multiple times, you should immediately contact a healthcare provider.

Headaches and stomach-related issues are a few other common side effects. Most symptoms will pass after a day or two. In cases where vomiting occurs shortly after ingestion, contact your healthcare provider before taking another dose.