Postmenopausal women who use oral menopausal hormone therapy are at risk of pulmonary embolism (PE) especially in the first 4 years of starting the therapy, according to a study published in the December 2022 issue of the journal Maturitas.¹ However, transdermal HRT was not associated with increase in the risk for PE.

In this study, Swedish researchers sought to examine the risk of pulmonary embolism in women who were taking menopausal hormone therapy. They attempted to categorize the risk based on the route of administration of the hormone therapy, duration and the type of progestin. For this, they screened 1,771,253 women, aged 40-69 years from 2005 to 2015 using data from the Total Population Register of Statistics Sweden. Women who had earlier been diagnosed with VTE were not included in the trial. A total of 13,974 women diagnosed with PE were included in the final analysis.

Women who were currently taking the menopausal hormone therapy were more likely to develop pulmonary embolism compared to those who were not using the hormone therapy with odds ratio of 1.15. The risk was doubled among those who were using it for the first time with OR 2.07. When the risk of PE was analysed according to the route of administration, no risk was found for transdermal administration. However, the risk was significantly higher in women who were using oral hormone therapy. A small increase in the risk was observed with the combination of estrogen and medroxyprogesterone (OR 1.60) vs estrogen and norethisterone acetate (OR 1.39), but this difference was non-significant. “The risk was considerably lower in women with recurrent treatment, probably because of the healthy user effect”, noted the authors.

Reference

1. Sundell M, et al. Pulmonary embolism in menopausal hormone therapy: a population-based register study. Climacteric. 2022 Dec;25(6):615-621. doi: 10.1080/13697137.2022.2127352.