US regulators approve new type of contraceptive gel

US regulators on Friday approved a birth control gel that works in a new way to prevent pregnancy.

Phexxi pronounced FECK'-see comes in an applicator that women insert before intercourse. The gel made by San Diego-based Evofem Biosciences contains lactic acid, citric acid and potassium bitartrate, all of which are common food additives.

The new gel has some similarities to spermicides, which block the entrance to the cervix and slow sperm down. But Phexxi works differently.

The vagina's pH a measure of acidity is usually in the range of 3.5 to 4.5, the level needed to maintain healthy bacteria. Sperm typically raise that to a more hospitable level of 7 to 8. Phexxi keeps it in the usual acidic range, killing the sperm.

Unlike some other contraceptives, it only needs to be taken shortly before sex and it doesn't contain hormones, which can cause side effects some women can't tolerate.