MJMR, Vol. 31, No. 4, 2020, pages (20-27). Hosny et al., 20 Obstetric Venous thromboembolism: A One-year Prospective Study in a Tertiary Hospital in Egypt. Research Article Obstetric Venous thromboembolism: A One-year Prospective Study in a Tertiary Hospital in Egypt. Mahmoud Hosny, Ahmed Reda, Ayman Nady, Hany Hassan and Mostafa Kamal. Department of Obstetrics and Gynecology, Faculty of Medicine, Minia University, Egypt Abstract Background and objective: Obstetric venous thromboembolism (VTE) poses a life-threating burden and it is one of the major causes of maternal morbidity and mortality with an increased incidence throughout the last decades. The objectives of this study were to assess the incidence of VTE, types of prophylaxis received and factors determining prophylaxis in women at VTE risk during pregnancy and puerperium at a tertiary hospital for one year. Methods: This is a prospective study that was carried out at Minia maternity university hospital, Egypt during the period from June 2018 to June 2019. The study included women attended the hospital at risk of VTE as per the RCOG guidelines. Full history, patient characteristics and VTE risk factors were assessed. Results: During the study period, a total of 901 women attended the hospital and perceived at risk of VTE (298 cases during pregnancy and 603 cases during puerperium), about half of them were mild in intensity. They comprise 8.22% of the total deliveries during the study period (n=10956). About two-thirds of them (71.5%) had a caesarean delivery. Varicose veins were found in 209 cases (23.2%), previous VTE in 189 cases (21.0%), previous superficial vein thrombosis was recorded in 240 cases (26.6%) and previous arterial ischemic events in 83 cases (9.2%). The vast majority of patients (99.6%) received the pharmacological type of prophylaxis (55.6% of them received unfractionated heparin and the rest of them 43.9% received Aspirin). Only 6 cases developed VTE from the total included cases with an incidence of 0.55/1000 maternities (0.055%). Obesity (BMI >30 kg/m2) and cesarean delivery were significant factors that determine VTE prophylaxis with an odds ratio of 1.68 (95% CI, 1.20-2.35, p<0.01) and 2.05 (95% CI, 1.49-2.80, p<0.01), respectively. Conclusion: The incidence of women perceived at VTE risk during the study period was 8.22% "which is lower than other studies", about half of them were mild in intensity. The risk of VTE was higher during the postpartum period than that during pregnancy. The incidence of VTE was 0.55/1000 overall maternities (0.055%). The pharmacological type of prophylaxis was the predominant used type. Obesity and cesarean delivery were significant factors determining VTE prophylaxis. Further large-scale prospective studies with longer duration are warranted to confirm our findings. Key words: Obstetric, Venous thromboembolism, Incidence, Prophylaxis Introduction Venous thromboembolism is a disease that influences venous circulation and distinctly presented by deep vein thrombosis (DVT) and pulmonary embolism (PE) [1] . Obstetric venous thromboembolism poses significant public health defiance and it is one of the foremost causes of maternal mortality and severe maternal morbidity, it has been reported that 51.4% of the women during pregnancy and postpartum were at risk of VTE [2] and about 9.2% of maternal deaths in the United States were caused by VTE with an observed increased incidence from 15.6 to 29.8 per 100,000 deliveries in short period (from 2006:2012) [3] . Other studies reported that the prevalence of VTE during pregnancy was 0.5-2.0/1000 pregnancies [4,5,6]. The risk of VTE increases by 6-fold during pregnancy however, it increases by 60-fold during puerperium [7,8]. Several factors are responsible for the increased risk of VTE during pregnancy "due to its related physiologic and anatomic changes" such as hypercoa- gulability, inferior vena cava and pelvic veins compression posed by uterus enlargement and