Continuous UFH should be adjusted to aPTT 2 times control. aPTT indicates activated partial thromboplastin time; IV, intravenous; LMWH, low-molecular-weight heparin; UFH, unfractionated heparin; and VKA, vitamin K antagonist. CLINICAL STATEMENTS AND GUIDELINES by switching to a heparin preparation before 5. Although LMWH does not result in an antico- agulated fetus, the risk of maternal hemorrhage is high if delivery occurs while the mother is on LMWH. Therefore, it is recommended that the mother be hospitalized before planned delivery, with discontinuation of long-acting anticoagu- lation and initiation of intravenous continuous infusion of UFH to keep aPTT >2 times control 6. Intravenous heparin should be stopped long enough before delivery to reduce risk of mater- nal bleeding and allow safe placement of epidural anesthesia (typically at least 6 hours). Exact tim- ing should be coordinated with the obstetrics and 7. Because warfarin results in an anticoagulated fetus, there is a high risk of fetal intracranial hemorrhage if vaginal delivery is attempted in a woman who is anticoagulated with warfarin. If a woman goes into labor while on warfarin, appropriate reversal of anticoagulation followed by cesarean section reduces the risk of fetal intra- 8. The teratogenic effects of warfarin are dose dependent. The rate of warfarin embryopathy is reduced (<3%) but not eliminated if the daily dose of warfarin is 5 mg/d.3,6.16,18,23,25,36,37 In most women, the effective dose of warfarin typically does not vary significantly during pregnancy.38 For women who require a dose 5 mg/d, continua- tion of low-dose warfarin throughout pregnancy poses the lowest combined risk to mother and The number of reported pregnancies on low-dose warfarin is relatively small, and not all publications have found improved fetal out- comes on low-dose warfarin,11 so caution should be exercised until more data are available. 9. 