THROMBOPROPHYLAXIS

Literature Review: Thromboprophylaxis During Pregnancy, Labour & Vaginal Delivery

Literature Review: Thromboprophylaxis During Pregnancy, Labour & Vaginal Delivery

Introduction

Most physicians and obstetricians would agree that women with a previous episode of thromboembolism and continuing risk factors such as inherited thrombophilia, the antiphospholipid syndrome or those with recurrent thromboembolic disease are at high risk of recurrence and should receive thromboprophylaxis throughout pregnancy and for 6 weeks postpartum (Stephen, 2002).

According to Thomas (2000) the indications for obstetric thromboprophylaxis are varied and no definitive guidelines exist due to the lack of prospective data. According to Horlocker (2005) the situation is perhaps less clear in women with a single episode of thromboembolism and no other risk factors. Their risk of recurrence is not known but this is likely to be low, perhaps of the order of 5 per cent or less. In these low risk women, the benefits of antepartum heparin prophylaxis may not outweigh the risks of developing heparin-induced osteoporosis. Although the use of antiplatelet agents for obstetric thromboprophylaxis has yet to be evaluated, meta-analysis of trials in surgical and medical patients suggests that they are a safe and effective alternative (Greer, 2002).

Kupferminc (2001) suggests that low dose aspirin is a safe and effective method of obstetric thromboprophylaxis in low risk women. According to Bates (2004) the prevention of deep vein thrombosis and pulmonary embolism is a ma?or consideration in all surgical patients. Unfortunately, the anaesthetic implications of thromboprophylaxis are rarely discussed, and this was once again the case in the study by Richard (2006).

Antenatal thromboprophylaxis should begin as early in pregnancy as practical. Postpartum prophylaxis should begin as soon as possible after delivery (but see precautions after use of regional anaesthesia) (Horlocker, 2005).

Postpartum thromboprophylaxis should be given as soon as possible after delivery, provided that there is no postpartum haemorrhage (Gibson, 2004: p109). Those with postpartum haemorrhage should be fitted with thromboembolic deterrent stockings. If the woman has been given regional analgesia, LMWH should be withheld until four hours after insertion or removal of the epidural catheter (or six hours if either insertion or removal were traumatic). The first postpartum dose can be given after insertion but before removal of the epidural catheter (Greer, 2002).

As the prothrombotic changes of pregnancy do not revert completely to normal until several weeks after delivery, postpartum thromboprophylaxis is normally continued for six weeks in high-risk women. In practice, this will mean women learning to in?ect themselves if they have not already commenced heparin antenatally (Thomas, 2000: p637). However, for women at lower risk, prophylaxis for three to five days is usually recommended, despite the lack of evidence in this area. Low risk includes those with two current or persisting risk factors as discussed in the table above and asymptomatic thrombophilias with low thrombotic risk (heterozygous factor V Leiden and prothrombin gene variant).The risk of VTE reduces when women are mobile postpartum but does not disappear. If the woman is discharged home early, her thromboprophylaxis should be continued at home, to complete the course of three to five ...