Fetal Warfarin Syndrome - A Case Report

Abstract

Fetal warfarin syndrome (FWS) or warfarin embryopathy also known as “Di Sala syndrome” is a rare fetal anomaly which occurs as a result of fetal exposure to warfarin during the early stages of pregnancy. FWS is characterised by nasal hypoplasia and skeletal abnormalities, including short limbs and digits and stippled epiphyses. Here we present a case of foetal embryopathy due to warfarin use in a female with an unplanned pregnancy while taking warfarin for cerebral venous thrombosis. The case was reported in Adverse Drug Reaction (ADR) Monitoring centre in August 2023. The purpose of this case report is to caution all the clinicians particularly obstetricians regarding the fetal abnormalities of warfarin. If the mother had history of warfarin usage, paediatricians should also be vigilant regarding the possibility of congenital warfarin syndrome in the newborn.
 Warfarin is an oral anticoagulant drug that decreases the production of clotting factors (II, VII, IX, X) which are vitamin K-dependent. Warfarin is used in the treatment of patients with thromboembolic disorders and in patients who are predisposed to the development of thrombus. Especially those people with prosthetic heart valves, those who have had ischemic stroke and atrial fibrillation. Warfarin is a teratogen which can cross the placental barrier and cause harm to the developing foetus.[1] Warfarin causes inhibition of clotting factors leading to internal bleeding of the fetus, while inhibition of osteocalcin retards bone growth. In addition to birth defects, warfarin can induce spontaneous abortion, premature delivery, neonatal death and even congenital anomalies known as fetal warfarin syndrome.[2] The risk of teratogenicity is not predictable with any dose of warfarin. The first case of embryopathy due to warfarin was reported by Di Sala in 1966 hence, it is also known as Di Sala syndrome.[3,4] Warfarin leads to embryopathy which is characterized by the abnormalities of cartilages and bones known as chondrodysplasia punctata.[5] Almost 6% of babies born to mothers treated with warfarin during the first trimester have a pattern of congenital anomalies like nasal hypoplasia and stippling of vertebrae or bony epiphyses.[6] So, warfarin is contraindicated during pregnancy.
 Here we present a case of foetal embryopathy due to warfarin use in a female with an unplanned pregnancy while taking warfarin for cerebral venous thrombosis. This form of stroke is relatively rare and underdiagnosed which accounts for 0.5%-1% of all strokes mostly occurring in young adults, especially in women. Pregnancy, use of oral contraceptive pills (OCPs), puerperium, malignancies and other conditions with hypercoagulable states have been recognised as predisposing risk factors.[7] The conventional therapy for venous thromboembolism includes treatment with parenteral low-molecular-weight heparin (LMWH) and the vitamin K antagonist warfarin.[7]