Millions of others take birth control pills that contain estrogen.
The law doesn't require anyone to take birth control.
Some women take birth control pills or rely on alternative medicines combined with frequent checks.
It's clearly silly to hold a hearing about contraception and not hear from anyone who might actually take birth control.
Death rates from pregnancy are higher than those from birth control, except among smokers who take birth control pills.
"If a Catholic woman wants to take birth control, to go behind her priest's back, that's between her and God," she said.
Many women who take birth control pills, for example, tend to have "stickier" blood vessels and arteries than men, he said.
Five per cent of people are pre-disposed to blood clots, yet doctors don't routinely screen women who take birth control pills because it is cheaper to treat them if they develop a blood clot.
He referred to the exceptional dispensation issued by one of his predecessors, Pope Paul VI, who permitted Catholic nuns in Africa to take birth control pills in the face of the risk of being raped.
Women who take birth control pills often have an increased risk of clots in the leg veins or the lungs, but aspirin is not known to decrease those risks, Dr. Manson said.
Dr. Alexandra Heerdt, a breast surgeon at Memorial Sloan-Kettering Cancer Center in Manhattan and director of special surveillance for high-risk women, said she had encouraged patients to take birth control pills to protect against ovarian cancer and that the new study had not changed her mind.
