Diagnosis Focus

More than half of all sexually active teen girls take combination hormonal contraceptives and many more teens take them to treat other health conditions. Contraceptive users are up to six times more likely to have a blood clot than non-users, and recent data indicate that as many as one in 10 females who experience blood clots are younger than 20.

“I tell my patients that if they are otherwise healthy and walk into an ER with leg or back pain or shortness of breath, no one is ever going to think of a blood clot — they have to tell the doctor they’re on a birth control pill,” says Sarah O’Brien, MD, a hematologist at Nationwide Children’s Hospital who studies venous thromboembolism (VTE) among contraceptive users.

Emergency nurses and physicians have the responsibility to respond appropriately as well, she says. “If the patient is on combined hormonal birth control, pulmonary embolism automatically has to be on the list of things to rule out,” says Dr. O’Brien.

Dr. O’Brien’s latest research suggests that reducing the incidence of VTE in teen girls could begin with thrombophilia screening of patients with a family history of the problem or who have other risk factors, such as smoking or obesity. But she cautions against screening too broadly. As many as 5 percent of U.S. Caucasians are carriers of the most common type of inherited thrombophilia, 90 percent of whom will never experience a complication.

Denying so many women the convenience of estrogen-containing birth control could actually cause more VTE-related problems than it avoids, Dr. O’Brien says, since the risk of blood clot during pregnancy is far greater than any increase from contraceptive use. Prescribing an estrogen-free birth control pill or finding alternative contraceptives are preferable solutions, she says. These changes could potentially reduce the risk for VTE in the highest-risk population and avoid underdiagnosis of VTE in emergency rooms, she adds.