Sarita, a 30-year-old woman develops a deep vein thrombosis in her left calf on the fouh postoperative day following cesarean section done for fetal distress. The patient is staed on heparin and is scheduled to begin a 6 weeks course of warfarin therapy. The patient Is a devoted mother who wants to breastfeed her baby. What is the advice which is given to the patient?

**Core Concept**
Warfarin is a vitamin K antagonist contraindicated in lactating women due to the risk of bleeding in the infant, whereas heparin does not cross the placenta and is considered safe during breastfeeding.

**Why the Correct Answer is Right**
Warfarin inhibits vitamin K-dependent clotting factors, which are essential for blood coagulation. When warfarin is taken by a lactating woman, vitamin K is reduced in breast milk, leading to clotting factor deficiency in the infant. This increases the risk of bleeding in the infant, which can be severe and life-threatening. In contrast, heparin does not cross the placenta and is not excreted in breast milk, making it a safer anticoagulant for lactating women.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not provide any information about the safety of warfarin during breastfeeding, which is the key concern in this scenario.
**Option B:** This option is incorrect because it does not address the specific question of whether warfarin is safe during breastfeeding.
**Option C:** This option is incorrect because it implies that heparin is contraindicated during breastfeeding, which is not the case.

**Clinical Pearl / High-Yield Fact**
Warfarin is a vitamin K antagonist that requires careful monitoring of INR levels to avoid bleeding complications. It is essential to inform lactating women about the risks of warfarin and to consider alternative anticoagulants like heparin or low molecular weight heparin.

**Correct Answer:** B.

✓ Correct Answer: D. Warfarin is not a contraindication for lactation