WASHINGTON — The Food and Drug Administration yesterday approved the first birth control pill that eliminates a woman’s monthly period.

Taken daily, the contraceptive, called Lybrel, continuously administers slightly lower doses of the same hormones in many standard birth control pills to suppress menstruation. It is designed for women who find their periods too painful, unpleasant, or inconvenient and want to be free of them.

“This will be the first and only oral contraceptive designed to be taken 365 days a year, allowing women to put their periods on hold,” said Amy Marren of Wyeth Pharmaceuticals, which expects Lybrel to be available with a prescription by July. “There are a lot of women who think that’s a great option to have.”

Company studies involving more than 2,400 women showed that Lybrel is as effective at preventing pregnancy as standard birth control pills and that it completely suppresses menstruation for many women within the first year, although some experience sporadic bleeding, the FDA said.

Advocates of birth control welcomed Lybrel, saying it provides women with another option.

“Every woman’s birth control needs are different, and the best methods are those that fit a woman’s lifestyle and meet her needs,” the vice president for medical affairs at the Planned Parenthood Federation of America, Vanessa Cullins, said.

But others questioned whether enough research was done to be sure that Lybrel is safe to suppress menstruation in the long term.

“There may be important health consequences that we don’t know about,” an endocrinology researcher at the University of British Columbia, Christine Hitchcock, said. “I don’t think we understand everything that the menstrual cycle does well enough to say with confidence that you can abolish it and not have any consequences.”

Some criticized Lybrel for fueling biases and misconceptions about menstruation.

“I think it sends the wrong message about menstruation in women’s lives, especially for young women,” an associate professor of psychology and women’s studies at the State University of New York at Fredonia, Ingrid Johnston-Robledo, said. “It perpetuates a lot of negative attitudes and taboos about menstruation — that it’s something that’s bothersome and dirty and debilitating and shameful.”