Table 86. Anticoagulation control in patients with mechanical prosthesis during pregnancy.

Gestational age (weeks)	Anticoagulant	Control
Between 6 and 12	Subcutaneous low-molecular-weight heparin 1.0 mg/kg every 12 hours or Intravenous unfractionated heparin 18 IU/kg/hour in an infusion pump (< 30,000 IU)	Anti-Xa: 0.8 to 1.2 U/ml aPTT 1.5 to 2.0 times control value
12 to 36	Warfarin, dose according to INR	Aortic INR between 2.5 and 3.0 Mitral INR between 3.0 and 3.5
After 36, until delivery	Low-molecular-weight heparin 1.0 mg/kg subcutaneous every 12 hours or Intravenous unfractionated heparin 18 IU/kg/hour in an infusion pump (< 30,000 IU)	Anti-Xa: 0.8-1.2 U/ml aPTT 1.5 to 2.0 times control value
Postpartum	Subcutaneous low-molecular-weight heparin 1.0 mg/kg every 12 hours Intravenous unfractionated heparin 18 IU/kg/hour in an infusion pump (< 30,000 IU) Warfarin must reach target INR before hospital discharge	Anti-Xa: 0.8 – 1.2 U/ml aPTT 1.5 to 2.0 times control value INR between 2.0 and 2.5

aPTT: activated partial thromboplastin time; INR: international normalized ratio.