**Core Concept**
Inherited thrombophilia testing in pregnancy involves the evaluation of genetic mutations that increase the risk of blood clots. This is crucial for identifying women at high risk of developing venous thromboembolism (VTE) during pregnancy. The tests focus on mutations in genes encoding proteins involved in blood coagulation.

**Why the Correct Answer is Right**
The correct answer is related to the genetic mutations associated with inherited thrombophilia. Factor V Leiden mutation, Prothrombin G20210A mutation, and Antithrombin deficiency are commonly tested in pregnant women to assess their risk of VTE. These tests help identify women who require closer monitoring and anticoagulation during pregnancy.

**Why Each Wrong Option is Incorrect**
* **Option A:** Factor V Leiden mutation is a common cause of inherited thrombophilia and is known to increase the risk of VTE during pregnancy. Therefore, it is used in inherited thrombophilia testing.
* **Option B:** Prothrombin G20210A mutation is another genetic mutation associated with an increased risk of VTE and is tested in pregnant women. Hence, it is not the correct answer.
* **Option C:** Antithrombin deficiency is a rare cause of inherited thrombophilia but is still tested in pregnant women at high risk of VTE. Therefore, it is not the correct answer.

**Clinical Pearl / High-Yield Fact**
Inherited thrombophilia testing is crucial in pregnant women with a history of VTE or a family history of VTE. The test results can guide anticoagulation therapy and reduce the risk of recurrent VTE.

**Correct Answer: D.**