Which condition occurs when the fetus compresses the inferior vena cava while the mother is lying supine, causing dizziness and hypotension?

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

Answer: (C)

Supine hypotensive syndrome occurs when a pregnant person, especially in the later stages, lies on the back. The enlarged uterus can press on the inferior vena cava, which reduces venous return to the heart. That drop in preload lowers cardiac output, leading to dizziness, lightheadedness, and hypotension in the mother. Fetal perfusion can also be compromised because blood flow through the placenta depends on adequate maternal blood flow. The key to relief is repositioning to the left side, such as the left lateral decubitus position, which relieves the pressure on the IVC and improves both maternal and fetal circulation. This scenario is distinct from the others: the first stage is a phase of labor, ectopic pregnancy involves implantation outside the uterus and may cause shock if rupture, and uterine rupture presents with sudden severe pain, abdominal signs, and rapid maternal and fetal deterioration—not simply dizziness from back-lying.