Woman who take estrogen and progestin, a combination hormone replacement therapy (HRT), have double the risk of developing blood clots. The findings add more grief to a growing list of risks associated with HRT, including, heart attack, breast cancer and stroke.
Researchers from the University of Vermont suggested women considering HRT who have a family history of blood clots should undergo testing to determine if they have a genetic predisposition.
The study involved 16,608 postmenopausal women between the ages of 50 and 79 years, were randomly assigned to receive either conjugated equine estrogen plus progestin or a placebo.
Venous thrombosis occurred in 167 women taking estrogen plus progestin and in 76 taking placebo.
The researchers also found the risk was even higher among older women as well as obese woman. Women 60 to 69 years had 4.28 times greater risk, and a 7.46 times greater risk for women aged 70 to 79 years.
Obese women had a 5.61 times the risk and overweight woman a 3.8 times greater risk.
“Estrogen plus progestin was associated with doubling the risk of venous thrombosis,” concluded the researchers.