In their commentary, Kannel and Levy1 thoroughly describe studies of the relationship between hormones, menopause, and CHD. They noted that CHD rises substantially after menopause, whether surgical or natural, and whether the ovaries were removed or not. What accounted for the low incidence of CHD before menopause remained unclear. They did not discuss whether menstrual blood loss could explain the finding.
Terplan M. Menstruation and Cardiovascular Vulnerability. Arch Intern Med. 2005;165(1):120. doi:10.1001/archinte.165.1.120-b