Oral contraceptives are among the carcinogens classified as “Group 1” by the International Agency for Research on Cancer (IARC), an agency that is part of the World Health Organization (WHO) of the United Nations. Group 1 carcinogens are substances which are “carcinogenic to humans.” In this group, estrogen-progestogen oral contraceptives (combined) are listed as Group 1 carcinogens. Ironically, there is also note that suggests that these substances could provide a protective effect against endometrial and ovarian cancers.
Group 2A denotes substances that are “probably carcinogenic to humans.” Group 2B denotes substances that are “possibly carcinogenic to humans.” In the latter group are listed progestins and progestogen-only contraceptives.
Despite the official classifications, there is ongoing research and documentation on the effects of these substances (increased rate of breast cancer, as well as strokes, heart attacks, blood clots, and HIV infections) on our young women and young families. Among several other sites, information can be found at the Breast Cancer Prevention Institute, www.bcpinstitute.org.