[Evidence] "Cardiovascular benefit has not been proven with micronized progesterone in observational or experimental research...a multicenter, case–control study was conducted in postmenopausal women aged 45–70 years to examine potential differences in cardiovascular risk between the subtypes of synthetic progestins and micronized progesterone...Micronized progesterone and pregnane derivatives were not associated with an increased venous thromboembolism risk, whereas norpregnane derivatives...were associated with increased risk of thromboembolism...Thus, certain progestins are associated with increased cardiovascular risk, whereas pregnane derivatives and micronized progesterone neither increase nor decrease cardiovascular risk in the doses studied" [Claim] 
The side effects reported in the Women's Health Initiative study were due to the synthetic nature of the hormones used