Background: Cesarean section increases four times the risk of venous thromboembolism compared to vaginal delivery. The Royal College of Obstetricians and Gynecologists guidelines are used at our service. A written alert was designed to stratify patients at high, intermediate or low risk making a suggestion for thromboprophylaxis. Aim: To assess the compliance with the guidelines and to evaluate the impact of a written alert in the thromboprophylaxis compliance in women subjected to caesarean section. Patients and Methods: Review of medical records of 233 women aged 19 to 32 years, subjected to a caesarean section in a Gynecology Service, between 2016-2017. Results: Compliance with recommendations was observed in 29% of patients (68/233), 86% in the low-risk group, 26% in the intermediate risk group and 100% in the high risk group. In 41/233 (18%) of patients, a written alert was included in the medical record. Compliance with recommendations in the presence of the written alert was 61% (25/41 women) compared to 22% (43/192) in those lacking the alert (p < 0.01). In women whose emergency caesarean section was the only risk factor, the compliance with the recommendation was 8%, compared with 30% among those who had at least one thrombotic risk factor associated with caesarean section (p < 0.01). Conclusions: In this cross-sectional study, we observed a low compliance with thromboprophylaxis guidelines in cesarean women. We observed that the use of a written alert improved the compliance with thromboprophylaxis.