Long-term safety of first-trimester warfarin exposure remains a key concern in pregnancies requiring anticoagulation for mechanical heart valves. In a single-center observational cohort study published in BMC Cardiovascular Disorders, long-term pediatric outcomes were assessed among children antenatally exposed to low-dose warfarin combined with enoxaparin, compared with enoxaparin alone.

The analysis included 32 children born to 30 women with mechanical heart valves enrolled at one center of the KYBELE study. Maternal anticoagulation data were obtained retrospectively, while pediatric outcomes were collected prospectively through standardized clinical evaluations. Children were categorized based on first-trimester anticoagulation regimen: enoxaparin only (n=12), enoxaparin plus warfarin 2.5 mg/day (n=8), or enoxaparin plus warfarin 4 mg/day (n=12).

At a median follow-up of 61.5 months, no child had growth parameters below the 3rd percentile. Prematurity occurred in 19% of cases, with no significant differences between groups (p=0.6). Developmental delay was observed in 2 children, without significant differences among groups (p=0.7). Hearing, vision, and thyroid function were normal across all participants. Minor neonatal echocardiographic findings were observed in 31% of children and resolved during follow-up, with no requirement for cardiac intervention. No skeletal abnormalities or features consistent with warfarin embryopathy were identified.

First-trimester exposure to low-dose warfarin with enoxaparin was not associated with major differences in long-term outcomes compared with enoxaparin alone. These findings may inform clinical decision-making when maternal indications exist.