Question

Deep vein thrombosis is more common in the left leg because

• A. of dextrorotation of uterus
• B. the left common iliac vein is more tortuous
• C. inferior vena cava is on right side
• D. left ovarian artery is a branch of aorta

Hint:

Think about which direction the pregnant uterus usually rotates and which vein that puts pressure on.

Answer 1

The Correct Option is A

Step 1: Recall the anatomy behind left-sided DVT in pregnancy.
Deep vein thrombosis in pregnancy happens more often on the left side, and the reason lies in how the pelvic vessels are arranged and how the growing uterus sits in the pelvis.

Step 2: Note the crossing of the vessels.
The right common iliac artery crosses over the left common iliac vein on its way down to the right leg. This crossing point alone puts some pressure on the left vein compared to the right.

Step 3: Add the effect of the growing uterus.
As pregnancy advances, the uterus commonly turns to the right, called dextrorotation of the uterus. This rotation pushes the enlarging uterus further against the left common iliac vein, adding to the compression already caused by the crossing artery, and slowing blood flow out of the left leg.

Step 4: Rule out the other options.
The left common iliac vein is not inherently more tortuous than the right, so option (B) is not correct. The inferior vena cava lying on the right side is true anatomy but is not itself the direct reason for more compression on the left vein. The left ovarian artery being a branch of the aorta is also a true anatomical fact but is unrelated to venous compression or clot risk in the leg.

Step 5: Final answer.
The added pressure from dextrorotation of the uterus on an already compressed left common iliac vein is why DVT favors the left leg.
\[ \boxed{\text{Dextrorotation of the uterus}} \]