Supine hypotensive syndrome

• Compression of the vena cava and pelvic veins by the uterus may occur during the third trimester of pregnancy (typically >20 weeks) as a result of the mother lying in a supine position.
  • Gravid uterus → compression of the abdominal aorta and IVC → impaired venous return and decrease in cardiac output → placental hypoperfusion → fetal hypoxia → deceleration (CTG)
  • After repositioning the mother in the left lateral position, the fetal heart rate recovers.
  • In the mother, supine hypotensive syndrome is characterized by tachycardia, dizziness, and nausea, and occasionally causes syncope.