(49) Hormonal contraceptive considerations in the setting of venous thromboembolism and absent inferior vena cava: A case report

Background: Venous thromboembolism (VTE) risk among users of contraception varies based on the hormonal composition of each method. Controversy exists regarding the use of hormonal contraception in those with a history of thrombosis or thrombophilia and require anticoagulation therapy.

Case: A 17 y.o. girl presented with persistent pain and swelling in both of her legs. Ultrasound confirmed bilateral femoral vein thromboses; CT revealed absence of the inferior vena cava (AIVC) with extensive thromboses through the iliac and femoral veins. She received therapeutic anticoagulation and mechanical thrombectomy. She reported a history of heavy menses and desired to initiate hormonal contraception for mitigation of heavy menstrual bleeding ultimately choosing the drospirenone 4mg contraceptive pill.

Comments: AIVC is a rare anomaly that affects < 1% of the population but commonly presents with lower extremity DVTs in young adults, requiring long-term or indefinite anticoagulation due to high rates of recurrence. Anticoagulation use in menstruating individuals has been associated with increased rates of abnormal uterine bleeding. Yet, there is some reluctance amongst health care providers to prescribe hormonal contraception in these circumstances due to increased risk of VTE, particularly with estrogen-containing methods. 2024 guidelines stratify risk based on: 1) current or history of VTE receiving therapeutic dosing of anticoagulants, 2) history of VTE receiving prophylactic dosing of anticoagulants without or with higher risk of recurrent VTE, and 3) history of VTE not receiving prophylactic dosing of anticoagulants. Though combination hormonal contraceptives (CHCs) do not appear to be associated with increased risk of recurrent VTE in those receiving anticoagulation therapy, CHCs are considered to have unacceptable risk in those with a high risk of recurrent VTE. Vascular malformations such as AIVC result in venous stasis and an increased risk of VTE with CHC use. In contrast, the menstrual and contraceptive benefits of progestin-only pills (POPs), the etonorgestrel implant, and the 52-mg levonorgestrel-releasing IUD (LnGIUD) usually outweigh the risk of recurrent VTE. A POP was deemed the most favorable option when prioritizing management of heavy bleeding in our patient given the possibility of breakthrough bleeding after initiation of LnGIUD, and the risk of irregular menstrual bleeding with the etonogestrel implant. Our patient chose the drospirenone 4mg contraceptive pill which may provide a more favorable bleeding profile with significantly lower rates of unscheduled bleeding compared to traditional POPs.