A television commercial for Barr Pharmaceuticals Inc.‘s Seasonale misleads consumers by excluding risk information to make the birth control pill seem safer, U.S. health regulators warned in a letter released on Thursday.

The commercial suggests use of the oral contraceptive leads to only four menstrual periods a year but fails to mention frequent and sometimes substantial bleeding, the FDA said in the Dec. 29 letter.

Barr’s advertisement plays down the risk of irregular menstrual bleeding that can be as heavy as a regular period by suggesting it would subside with continued use of the pill, the letter said.

The FDA posted the letter Thursday on its Web site at http://www.fda.gov/cder/warn