Which of the following congenital malformation is seen in a child of a mother who is on treatment with oral anticoagulants – a) Craniofacial malformationsb) Renal agenesisc) Long bone defectsd) Chondrodysplasia punctata

**Core Concept**
The question tests the understanding of teratogenic effects of oral anticoagulants, specifically warfarin, on fetal development. Warfarin crosses the placenta and can cause **congenital malformations**.

**Why the Correct Answer is Right**
Warfarin use during pregnancy is associated with **chondrodysplasia punctata**, a rare genetic disorder characterized by the formation of spots near the ends of bones and cartilage. This condition results from the inhibition of vitamin K-dependent enzymes, essential for bone and cartilage development.

**Why Each Wrong Option is Incorrect**
**Option A:** Craniofacial malformations can be caused by various teratogens but are not specifically linked to oral anticoagulants.
**Option B:** Renal agenesis is associated with genetic and environmental factors but not directly with warfarin.
**Option C:** Long bone defects are linked to different conditions and not typically with warfarin exposure.

**Clinical Pearl / High-Yield Fact**
Warfarin's teratogenic effects are most pronounced during the first trimester, making it crucial to avoid its use during this period.

**Correct Answer:** D. Chondrodysplasia punctata