The influences of sex hormone therapy – for contraception, treatment of heavy menstrual bleeding, hormone-replacement therapy, gender-affirming care therapy, etc. – on venous thrombotic and cardiovascular risk was explored in a Review Article published April 15 in NEJM.

Leslie Skeith, MD, and Shannon M. Bates, MD, describe the effects of different sex hormones on hemostasis, the vasculature and an individual's risk of thrombosis. They note that individuals taking oral contraceptives with a combination of hormones experience an increased risk of venous thromboembolism (VTE) by a factor of 3.5, while risk of VTE in individuals undergoing hormone-replacement therapy increases by a factor of two. In most cases, they note, absolute risk of the outcome is low.

The authors also share guidance on the prevention and treatment of hormone-associated VTE, suggesting a levonorgestrel-releasing intrauterine system or low-dose progestin for those considering contraception at increased risk for VTE and transdermal estradiol for those looking to undergo hormone-replacement therapy or gender-affirming hormone therapy. The studies included in their review also demonstrate that micronized progesterone has a low thrombotic risk.

Skeith and Bates also advise that most patients with previous hormone-associated VTE can discontinue anticoagulant therapy after three to six months, so long as hormone therapy has also ceased. With ongoing, well-managed anticoagulation, their review supports continuing hormone therapy. They add there is no increased risk of VTE associated with testosterone replacement, but more studies looking at the transmasculine population are needed.

Addressing perioperative management of hormone therapy, the authors recommend "continuing hormone therapy around the time of surgery and using thromboprophylaxis, depending on the clinical scenario...The decision to continue such therapy should be based on an informed discussion of the benefits and drawbacks of doing so, as well as appropriate use of thromboprophylaxis."