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How did the PrenaBelt™ attachments get their names? (CA)

How did the PrenaBelt® attachments get their names? Their names are more than just cute baby names! The names of the PrenaBelt® attachments are inspired by the night sky, which we associate with natural sleep. Our goal with the PrenaBelt® is to help you sleep safe and sound in late pregnancy. Every night.

Luna

Norma

Aurora Attachment

Ursa

Carina

Nebula

Vela

How did the PrenaBelt™ arc-and-circle come to be?

 

For the visual learners, watch our explainer video below! Cliquez ici pour regarder la vidéo en Français

For those who prefer reading, continue reading below (reading time ~5 minutes).

The PrenaBelt™ arc-and-circle logo graphically represents the physiology of the effect of pelvic tilt in the third trimester of pregnancy on aortocaval compression. "Aortocaval compression" refers to the compression of two major blood vessels, the abdominal aorta and inferior vena cava, by the enlarging womb (uterus) in late pregnancy. These vessels are squeezed between the uterus and the bones of the spine. The abdominal aorta is an artery that carries oxygenated blood from the heart to the pelvis, uterus, and legs - this vessel is thick-walled and under high pressure and, therefore, can resist compression from the weight of the uterus. The inferior vena cava is a vein that carries deoxygenated blood from the legs, uterus, and pelvis back to the heart - this vessel is thin-walled and under low pressure and, therefore, is susceptible to compression from the weight of the uterus as the pregnancy advances and the uterus enlarges.  

When a pregnant person in their third trimester lies on their left side as seen in the photo below on the left, their uterus is no longer compressing their abdominal aorta or inferior vena cava. Let’s define this as 90° of pelvic tilt. The corresponding image on the right is an MRI showing a cross section of a 42 year-old pregnant woman lying on her left side at 39 weeks’ gestation. The image is taken at her L2-L3 disk level. The red circle from the PrenaBelt arc-and-circle logo represents the cross-sectional area of the aorta and corresponds to the red overlay delineating the aorta on the MRI image. The purple bar from the PrenaBelt arc-and-circle logo represents the vertical height of the inferior vena cava and corresponds to the purple overlay delineating the inferior vena cava on the MRI image. 

As she rolls towards her back, her enlarged uterus begins to push on her abdominal aorta and inferior vena cava. The photo on the left demonstrates 30° of pelvic tilt. The corresponding MRI image shows the cross section of a 39 weeks’ pregnant woman at 30° of pelvic tilt. The purple bar on the arc traces the vertical height of the inferior vena cava. Again, the red and purple overlays delineate the vessels on the MRI image. The cross-sectional area of the abdominal aorta and inferior vena cava are essentially unchanged as the aortocaval compression at this angle of pelvic tilt is minimal.

As she rolls further towards her back, her enlarged uterus begins to compress her abdominal aorta and inferior vena cava. The photo demonstrates 15° of pelvic tilt. The corresponding MRI image shows the cross section of a 39 weeks’ gestation woman at 15° of pelvic tilt. The purple bar on the arc continues to trace the vertical height of the inferior vena cava, which is now rapidly decreasing due to compression from the uterus. Again, the red and purple overlays delineate the vessels on the MRI image. The cross-sectional area of the abdominal aorta is still unchanged due to the muscular and thick wall of this high-pressure vessel. However, at this angle of pelvic tilt, the weight of the uterus resting directly on the relatively low-pressure inferior vena cava compresses it significantly.

Finally, when flat on the back in the third trimester of pregnancy, the enlarged uterus compresses her abdominal aorta and inferior vena cava. The photo demonstrates 0° of pelvic tilt. The corresponding MRI image shows the cross section of a 39 weeks’ pregnant woman at 0° of pelvic tilt or flat on the back. The purple bar on the arc shows the vertical height of the inferior vena cava, which is now minimal. Again, the red and purple overlays delineate the vessels on the MRI image. The cross-sectional area of the abdominal aorta remains unchanged. However, at 0° of pelvic tilt, the inferior vena cava is completely occluded by the weight of the overlying uterus.

 

Reference:

Higuchi H, et al. Effect of Lateral Tilt Angle on the Volume of the Abdominal Aorta and Inferior Vena Cava in Pregnant and Nonpregnant Women Determined by Magnetic Resonance Imaging. Anesthesiology, 2015.

 

 

Disclaimer: The information provided on this page is for informational purposes only and is not professional medical advice, diagnosis, treatment, or care, nor is it intended to be a substitute therefore.

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