In which condition does the weight of the fetus compress the inferior vena cava when the mother is supine?

• A. Nuchal cord
• B. Prolapsed cord
• C. Preeclampsia
• D. Supine hypotensive syndrome

Answer: (A)

When a pregnant person in the later stages lies on their back, the enlarged uterus can press on the inferior vena cava, reducing venous return to the heart. That drop in preload lowers cardiac output and can cause maternal hypotension, which in turn decreases placental perfusion and can lead to fetal distress. This positional vascular compression is the condition described, often called supine hypotensive syndrome.

The other scenarios involve different problems: issues with the umbilical cord (such as a nuchal cord or prolapsed cord) affect fetal circulation in ways not caused by maternal IVC compression, and preeclampsia is a maternal hypertensive disorder with systemic effects, not primarily a result of sleeping on the back. In practice, relieving the compression by placing the mother in the left lateral decubitus position (with possible leg elevation and careful monitoring) is the key management step to restore venous return and stabilize both mother and fetus.