Left uterine displacement (LUD) is a physical maneuver performed on pregnant individuals, typically in the later stages of gestation, to manage medical emergencies. The procedure involves gently shifting the large, heavy uterus away from the center of the body. This action is designed to reposition the weight of the womb and its contents. LUD is a medical intervention generally performed by trained professionals in emergency or surgical settings.
The Physiological Need for Displacement
The necessity for uterine displacement arises from a condition known as Aortocaval Compression Syndrome, also commonly called Supine Hypotension Syndrome. This occurs when a pregnant person lies flat on their back, a position known as supine, usually after the 20th week of pregnancy. In this position, the substantial weight of the gravid uterus presses directly onto major blood vessels running along the spine.
The compression primarily affects the inferior vena cava (IVC), the large vein responsible for returning deoxygenated blood from the lower body to the heart. This pressure significantly reduces the amount of blood returning to the heart, which in turn lowers the mother’s cardiac output and blood pressure. The aorta, the body’s main artery, can also be compressed, though less frequently, further compromising systemic circulation.
The resulting decrease in maternal blood flow can lead to symptoms in the mother such as dizziness, nausea, and a drop in blood pressure. The reduced circulation can also impair blood flow to the placenta, potentially compromising oxygen and nutrient delivery to the fetus. Performing LUD is a rapid, non-invasive method to relieve this vascular compression and restore adequate circulation to both the parent and the fetus.
Step-by-Step Manual Technique
The most immediate and direct method to relieve aortocaval compression is the manual technique, which can be executed quickly in an emergency. The operator, often standing on the patient’s right side, places their hands on the pregnant abdomen. This positioning allows for maximum leverage and control over the organ.
The technique involves cupping the uterus with one or both hands, applying firm and sustained pressure. The goal is to lift the entire mass of the uterus and push it laterally toward the patient’s left side. This physical shift effectively moves the womb off the spine and the compressed blood vessels.
Single-Handed Approach
When utilizing a single-handed approach, the operator places the heel of their hand against the right side of the abdomen and uses their fingers to sweep or push the bulk of the uterus to the left.
Two-Handed Approach
The two-handed technique, often preferred for increased force and endurance, involves the operator using both hands, stacked or side-by-side, to achieve the same displacement.
Maintaining this pressure is essential, as the uterus will immediately fall back to the central position. This manual displacement must be maintained continuously for the duration of the emergency, such as during cardiopulmonary resuscitation (CPR) or until the patient’s blood pressure stabilizes. In some high-acuity situations, a dedicated provider is assigned solely to maintain the LUD. The constant, active pressure ensures the vena cava remains decompressed, maximizing blood return to the heart during resuscitation efforts.
Alternative Positioning Strategies
Beyond the active manual push, there are several passive positioning strategies that achieve left uterine displacement using mechanical assistance. These methods rely on physically tilting the patient’s body to shift the uterus by gravity. A common strategy involves using a specialized wedge, a rolled blanket, or a firm pillow placed underneath the patient’s right hip and lower back.
The purpose of the wedge or blanket is to create a tilt of approximately 15 to 30 degrees to the left. This angle is generally considered sufficient to move the uterus off the major blood vessels, leveraging gravity to maintain the displacement passively. While this angle is effective for many situations, a patient may sometimes need a greater degree of tilt to achieve full vascular decompression.
In operating rooms or during transport, specialized medical equipment can be used to achieve this lateral positioning. Operating tables and transport stretchers are frequently equipped with mechanisms that can be tilted up to 30 degrees to the left. This full table tilt provides a consistent, hands-free method of displacement. While these passive methods are useful in non-emergency settings, manual displacement is often preferred during active CPR, as a significant body tilt can interfere with the effectiveness of chest compressions.