Estrogen seems to have significant protective effects against atherosclerosis during the pre-, peri-, and early postmenopausal years, but may have deleterious effects during the late postmenopausal years, according to a recent report in 

Thomas B. Clarkson, DVM, says that during the premenopausal years, both women and monkeys with estrogen deficiency develop premature atherosclerosis, which can be largely prevented with combination OCs.  

Concerning the peri- and early post-menopausal years, he reports that monkeys given estrogens immediately after surgical menopause have a 70% inhibition in coronary atherosclerosis progression. Similarly, the Estrogen in the Prevention of Atherosclerosis Trial, a meta-analysis of women younger than 60 years, showed that those given combination hormone therapy had reduced total mortality (RR = 0.61; 95% CI, 0.39–0.95). 

Clarkson TB. Estrogen effects on arteries vary with stage of reproductive life and extent of subclinical atherosclerosis progression. 

Estrogen seems to have significant protective effects against atherosclerosis during the pre-, peri-, and early postmenopausal years, but may have deleterious effects during the late postmenopausal years, according to a recent report in Menopause.