In plain words
Inferior vena cava compression happens when the growing uterus presses on the large vein that carries blood from the lower body back to the heart. Lying flat on the back, especially in the later weeks, can make this worse. Blood flow to the heart can drop, and you may feel dizzy, lightheaded, short of breath, or sweaty. Some people feel faint. Many mothers notice it only when they lie down, and find that rolling onto one side helps. It is common in later pregnancy and is usually harmless. Still, , chest pain, a racing heart, or new trouble breathing need prompt medical attention. Call 911 for those signs. Dizziness that is new, frequent, or does not ease with a change of position is worth mentioning to a provider.
The deeper version
by the gravid uterus in the supine position reduces venous return, cardiac output, and blood pressure, a pattern called . Frequency rises in the third trimester. Sympathetic compensation maintains flow in most people, and symptoms depend on the degree of compression and on collateral venous flow through vertebral and azygos routes. Left lateral positioning relieves symptoms for most. ACOG Committee Opinion 804 (2020) on physical activity in pregnancy addresses supine positioning in light of reduced cardiac output. Controversy persists over how often symptoms signal fetal compromise, and evidence for severity thresholds is limited.
Where it comes up
- Moving your body in pregnancyPregnancy: Your Body
- Swelling: feet, ankles, hands, facePregnancy: Your Body
What mothers here say about inferior vena cava compression
No one has posted under this term yet.
Sources
- American College of Obstetricians and Gynecologists — Committee Opinion 804: Physical Activity and Exercise During Pregnancy and the Postpartum Period, 2020