A new statistical analysis finds that woman under the age of 50 who were diagnosed with breast cancer were also more likely to have recently been on some form of birth control pills.
To examine the risk in a group of women more recently on birth control pills, Beaber’s team analyzed data from a large healthcare delivery system, tracking birth control pill prescriptions and breast cancer diagnoses. The researchers compared 1,102 women diagnosed with invasive breast cancer between 1990 and 2009 with 21,952 women without cancer who were of similar age. Women who had taken oral contraception during the past year, according to pharmacy records, were more likely to be in the cancer group than those who had never taken birth control pills or who had taken them more than a year prior. Contraceptives with higher doses of estrogen or progestin were more strongly associated with increased cancer risk.