Table 1.
Safety of anticoagulant use in pregnancy
| Anticoagulant | Safety and Use in Pregnancy |
|---|---|
| LMWH | Enoxaparin, Daltaparin; dose 1 mg/kg BID; does not cross the placenta, blood thinner of choice in pregnancy; may need to adjust dose with increasing weight/may need to monitor anti-Xa levels (goal 0.5–1.1 U/mL). |
| UFH | May be used in place of LMWH in setting of renal dysfunction, high-risk PE, or during delivery, as it has a short half-life; IV drip or injections; need to monitor anti-Xa levels as volume of distribution and weight changes during pregnancy. |
| NOAC/DOAC | Clinical trials for DOACs/NOACs excluded pregnant women. Association with congenital anomalies, bleeding, implantation failure in animal studies. Slight increase in risk in human reports. Registry available: http://www.surveygizmo.com/s3/2394649/international-registry-of-pregnancy-during-NOAC-use-inclusion. |
| VKA | Warfarin crosses the placenta and has potential of teratogenicity; 3.7%–6.4% risk of congenital abnormalities. Also risk of fetal hemorrhage after organogenesis. Should not be used for treatment of VTE in pregnancy. |
| Synthetic heparins | Fondaparinux is not thought to increase risk of congenital malformations. Small amounts cross the placenta and 10% detected in neonates’ blood with measurable effect on neonatal anti-Xa levels. This effect was not enough to lead to a full antithrombotic effect; hence clinical significance of placental transfer is unknown. |
| Thrombin inhibitors | Lepirudin is not expected to increase the risk of congenital anomalies. Human case reports and animal studies do not show evidence of malformation. Lepirudin does cross the rat placenta. Argatroban use in animal studies was performed at doses lower than human doses. Rare case reports do not show evidence of congenital anomalies; safety cannot be ascertained. Argatroban has been used in cases of HIT and heparin allergy. |
Abbreviations: BID, twice daily; HIT, heparin-induced thrombocytopenia; IV, intravenous; LMWH, low molecular weight heparins; NOAC/DOAC, novel/direct anticoagulants; PE, pulmonary embolism; UFH, unfractionated heparins; VKA, vitamin K antagonists; VTE, venous thromboembolism.