Which factor best explains why the supine position should be avoided during labor?

Which factor best explains why the supine position should be avoided during labor?

• A. It reduces fetal heart rate variability
• B. It bears no effect on fetal oxygen
• C. It compresses the aorta and inferior vena cava, causing maternal hypotension and fetal hypoxia
• D. It improves placental perfusion

Answer: (C)

When a pregnant person lies on their back, the growing uterus can press against the aorta and the inferior vena cava. This aortocaval compression reduces venous return to the heart and lowers maternal cardiac output, which in turn decreases placental blood flow. With less blood reaching the placenta, oxygen delivery to the fetus drops, increasing the risk of fetal hypoxia or distress. Placing the person on the left side relieves this compression, improves venous return, and enhances placental perfusion, benefiting both mother and baby. The idea that the supine position has no effect on fetal oxygen or that it improves placental perfusion isn’t correct; the primary issue is the compression causing reduced uteroplacental blood flow and maternal hypotension.

When a pregnant person lies on their back, the growing uterus can press against the aorta and the inferior vena cava. This aortocaval compression reduces venous return to the heart and lowers maternal cardiac output, which in turn decreases placental blood flow. With less blood reaching the placenta, oxygen delivery to the fetus drops, increasing the risk of fetal hypoxia or distress. Placing the person on the left side relieves this compression, improves venous return, and enhances placental perfusion, benefiting both mother and baby. The idea that the supine position has no effect on fetal oxygen or that it improves placental perfusion isn’t correct; the primary issue is the compression causing reduced uteroplacental blood flow and maternal hypotension.