TITLE: First Trimester Deep Vein Thrombosis Associated with Hyperemesis GravidarumINTRODUCTION: Pregnancy infers a 5x increased risk of venous thromboembolism (VTE). Up to 40% of antenatal VTE occur in the first trimester, often prior to initiation of prenatal care. If thrombogenic risk factors are identified early, appropriate thromboprophylaxis can decrease associated complications of VTE.CASE DESCRIPTION: A 30-year-old G5P2022 at 9 weeks gestation presented to the hospital for intractable nausea, vomiting, weight loss, volume depletion, and ketonuria. A clinical diagnosis of hyperemesis gravidarum was made. She was given a bolus of lactated ringers in 5% dextrose and subsequently admitted for further administration of fluid maintenance and antiemetic therapy. She had minimal improvement in symptoms over the following 24 hours and was unable to advance diet from clear liquids. The following morning, she reported new onset tenderness in her left groin and lower extremity upon ambulation. Physical exam was notable for a positive Homan's sign and a difference in calf circumference of 8cm. Although pneumatic compression devices were ordered, they were not utilized overnight secondary to patient discomfort and inability to sleep with use.DISCUSSION: A STAT compression ultrasound was ordered and therapeutic low-molecular-weight heparin was given for presumed venous thrombus. Imaging showed an acute occlusive venous thrombus of the left common femoral vein, femoral vein, and popliteal vein with a superficial thrombus seen in the proximal portion of the great saphenous vein. Interventional cardiology was consulted. Thrombectomy was performed under ultrasound guidance, and 80-90% of the clot burden was removed. The patient was later discharged home in stable condition on intravenous antiemetics with plan to continue therapeutic low-molecular-weight heparin until six weeks postpartum.CONCLUSION: Anatomic and physiologic changes of pregnancy begin as early as the fourth week of pregnancy and Result in a prothrombotic state. Thrombotic risk is further increased by early pregnancy complications such as hyperemesis gravidarum. VTEs account for an estimated 10-15% of maternal deaths in high-resource countries. This case highlights the need for routine use of risk assessment tools in early gestation so that adequate thromboprophylaxis may be initiated to prevent maternal morbidity and mortality.