Side effects of Plan B include nausea, which 1 in 4 women experience, and, less frequently, vomiting, abdominal pain, dizziness and breast tenderness. But beyond those immediate effects, doctors say Plan B is extremely safe and effective. "There are no medical contraindications, and it doesn't interact with other drugs," Chen says.
One reason it's safe is that, even though Plan B is similar to birth control pills, it has no estrogen in it — only levonorgestrel, a progestin hormone. That means Plan B does not carry the risks of blood clots that pills containing estrogen do. Also, Plan B is a single dose drug, not something women take every day (or nearly every day).
Advocates say that restricting access to emergency contraception leaves young teens facing unwanted pregnancy. Nearly 750,00 girls aged 15-19 get pregnant each year in the US, and 59% of those pregnancies are carried to birth. "It's preposterous to allow a teen to become pregnant when there is a safe, nontoxic method to prevent that from happening," says Corinne Rocca, a researcher at UCSF's Bixby Center for Global Reproductive Health.
Similar products are available over-the-counter in other countries, such as Belgium, Sweden, the Netherlands, South Africa and Thailand with no specific age restrictions. In Britain, France, Australia and China, emergency contraception can be purchased from pharmacists without a prescription but is kept behind the counter, as it is in the U.S.
In Britain, buyers have to be at least 16. In France and Belgium, the medication is provided free of charge for girls younger than 18 without an age restriction.
