Beverley Hunt

Incidence and management of 82 cases of pregnancy-associated venous thromboembolism occurring at a single centre – Response to Lyall & Myers

ed heparin (UFH; 1999–2003) or LMWH. The majority of the patients received enoxaparin (twice daily); a few had dalteparin (twice daily) or tinzaparin (once daily). Anticoagulation was continued throughout pregnancy and puerperium at therapeutic doses for at least 3 months. After this, most antenatal cases had the intensity reduced. All women were able to comply; however, there was some crossover between products (allergic type skin reactions). The optimal LMWH management regimen for antenatal VTE is not known. In our experience it may be possible to reduce the intensity after 3 months if the event had occurred early in pregnancy, reducing both frequency of injections, and complications if labour occurs unexpectedly. This area requires further study. Details of labour management were obtained in 52 cases: UFH bridging-therapy occurred in 14 cases (27%), reduceddose LMWH in 36 cases (69%) and full-dose LMWH in two cases (4%). UFH, where used, was stopped during established labour. Women were advised to omit LMWH if they suspected labour was commencing. Two women had inferior vena cava filters inserted. Voke et al (2007) suggested that 9/128 patients had intravenous heparin around labour and no comment was made regarding how LMWH-dosing was interrupted in the other cases. This is important because, if labour is initiated whilst the mother is fully or partially anticoagulated, the obstetric management may be modified to accommodate this, introducing other risks. In our series there were no peripartum thrombotic events, suggesting that a risk-assessed tailored plan is feasible. Two cases of secondary postpartum haemorrhage occurred, both following caesarean section. Heparin was restarted within 24 h postprocedure and warfarin within 72 h in both cases. In conclusion, our data on the incidence and risk factors for pregnancy-associated VTE agree closely with the findings of Voke et al (2007). The optimum management of this condition however is not known. In our experience a variety of strategies can be used, tailored to the needs and thrombotic risks associated with each patient. We agree with Voke et al (2007) that this is an area that requires further study.