807: Thromboprophylaxis in pregnancy the practical implications of guidelines

Abstract

Pregnancy increases the risk of thromboembolic disease (TED) such that it is reported to complicate one in 500 to 2000 maternities. The case fatality rate for pulmonary embolism (PE) is high, however, making TED the leading direct cause of maternal mortality in the UK and Northern Ireland (1.94 per 100,000 maternities). Recent guidelines have been produced by the RCOG in the UK that have been rapidly adopted by hospital trusts. Pregnant women are assessed for risk of thrombosis (low, intermediate or high) using a combination of multiple risk factors at booking, during hospital admission antenatally and around the time of delivery. Low Molecular Weight Heparin (LMWH) administration is recommended for those deemed to be at intermediate or high risk. The aim of this study was to determine how this risk stratification would apply to our obstetric population and what number of patients would potentially receive LMWH. The charts of the first 100 women who delivered at the CWIUH in 2010 were reviewed and risk stratification applied at the relevant time points. Out of this population, a total of 51 women i.e. 51% were deemed to be at high or intermediate risk of TED at the some point during pregnancy; 5 at booking, 7 during an antenatal admission, and 39 peri-partum. Of these peri-partum cases, 14 had undergone either elective or emergency caesarean section while the remainder of 25 were deemed at intermediate risk due to having a combination of two or more of the following; parity greater than or equal to 3, smoking, BMI >30 or age greater than 35 years. Identification of women at high risk of TED in pregnancy remains paramount and the RCOG guidelines are excellent in this regard. However, the use of multiple risk factors cumulatively (that individually have low impact on thrombotic risk in pregnancy) places many women into an intermediate risk category. The efficacy, safety and cost effectiveness of treating one out of every two women in order to prevent a complication that occurs at most in only one out of every 500 maternities needs greater evaluation.