How is protein S deficiency treated during pregnancy?

Updated: Jan 03, 2021
  • Author: Mohammad Muhsin Chisti, MD, FACP; Chief Editor: Perumal Thiagarajan, MD  more...
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In patients with heterozygous protein S deficiency and no history of thrombosis, physicians may administer prophylactic heparin during situations that present high risk for thrombosis. Such situations include surgery, orthopedic trauma (especially with a cast), pregnancy, and prolonged bed rest. Heparin may be administered subcutaneously in standard protocols for venous thromboembolism (VTE) prevention.

The risk of VTE during pregnancy and for the first 6 weeks postpartum varies among the hereditary thrombophilic states. Protein S and protein C deficiencies significantly elevate the risks for thrombosis when compared with the modest increase in thrombosis seen with factor V Leiden mutation. Protein S deficiency was also associated with a seven-fold increase in fetal loss. Many experts recommend that women with protein S deficiency and a history of fetal loss, and severe or recurrent eclampsia, receive low-dose aspirin and prophylactic-dose low molecular weight heparin (LMWH) therapy during pregnancy, with the LMWH prophylaxis extending for 6 weeks postpartum.

For women with heterozygous protein S deficiency and no prior VTE or history of fetal loss, treatment choices vary. Some experts recommend VTE prophylaxis only during the 6 weeks postpartum (the highest risk period for VTE) unless the pregnancy is complicated. Others recommend prophylaxis for the entire pregnancy and 6 weeks postpartum. Recommendations for other scenarios include the following:

  • For women with no prior history of VTE and protein S deficiency plus any other thrombophilic defect, active prophylaxis with LMWH should be given during pregnancy and for 6 weeks postpartum.

  • For women with a prior VTE history and confirmed protein S deficiency, experts recommend prophylactic or intermediate dosing of LMWH during pregnancy and for 6 weeks postpartum.

  • For women with a prior history of VTE who are already receiving oral anticoagulants at the time of pregnancy, full anticoagulant dosing of LMWH is recommended with transition back to oral anticoagulant postpartum.

  • Patients with recurrent thrombosis should remain on lifelong warfarin.

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