What condition occurs when a pregnant woman lies on her back and the fetus compresses the inferior vena cava, causing dizziness and hypotension?

• A. First stage
• B. Supine hypotensive syndrome
• C. Ectopic pregnancy
• D. Uterine rupture

Answer: (B)

When a pregnant woman in the later stages lies on her back, the enlarged uterus can press on the inferior vena cava, reducing venous return to the heart. This drop in preload lowers cardiac output, causing dizziness and low blood pressure. Repositioning to the left side (left lateral tilt) relieves the compression, improves venous return, and stabilizes both mother and fetus. The other options don’t describe this positional vascular compression: first stage is a phase of labor, ectopic pregnancy involves implantation outside the uterus, and uterine rupture is a dangerous rupture of the uterus, not a hemodynamic effect from lying supine.