Wharton’s jelly is the soft, gel-like tissue that fills the umbilical cord, cushioning and protecting the blood vessels that carry oxygen and nutrients between a pregnant person and their developing baby. It makes up the bulk of the cord’s volume and plays a critical role in keeping blood flowing smoothly throughout pregnancy. Named after the 17th-century English physician Thomas Wharton, this tissue has gained significant attention in recent years because of the stem cells it contains.
What Wharton’s Jelly Is Made Of
Wharton’s jelly is a type of connective tissue, but it’s unlike anything else in the human body. Its main ingredient is hyaluronic acid, a water-attracting molecule that pulls in and holds large amounts of fluid. This creates the thick, hydrated gel that gives the umbilical cord its firm, rubbery texture. Threaded through this gel is a network of collagen fibers (primarily types I, V, and VI) that provide structural support.
Scattered throughout the matrix are specialized cells that behave like a cross between connective tissue cells and muscle cells. These stromal cells can contract, and researchers believe they actively help regulate blood flow through the umbilical vessels rather than just sitting passively in the gel. The tissue is organized into three distinct zones: an outer layer just beneath the cord’s surface membrane, a middle layer, and a dense region packed tightly around the blood vessels themselves.
How It Protects the Baby During Pregnancy
The umbilical cord typically contains three blood vessels: two arteries and one vein. These vessels are the baby’s lifeline, and if they get kinked or compressed, blood flow drops and the baby can be deprived of oxygen. Wharton’s jelly prevents this by acting as a physical buffer. Its water-saturated gel absorbs pressure from the outside, so when the cord bends, loops around the baby, or gets pressed against the uterine wall, the vessels inside stay open.
This protective function depends on having enough jelly in the right consistency. When Wharton’s jelly is reduced or absent in sections of the cord, the consequences can be serious. Thinned-out areas leave blood vessels vulnerable to compression, which is a direct cause of stillbirth, fetal growth restriction, and distress during labor. On the other end of the spectrum, excess jelly or swelling (edema) in the cord can also signal problems. Structural abnormalities like pseudocysts and tissue breakdown have been documented as well.
Ultrasound measurement of the jelly’s cross-sectional area is showing promise as a way to assess placental health during pregnancy. A smaller-than-expected area correlates with placental problems and restricted fetal growth, potentially giving doctors an early warning sign.
Where It Comes From in Development
Wharton’s jelly forms early in pregnancy from tissue called extraembryonic mesoderm, the same layer that gives rise to the cord’s blood vessels and surrounding structures. This means it develops outside the embryo itself, which is part of what makes its cells biologically distinctive. Even before the cord is fully formed, this primitive jelly already plays a role: it surrounds early blood-forming cells as they migrate through the embryo during development, essentially providing a supportive environment for the earliest stages of the blood system.
Why Stem Cell Researchers Are Interested
The stromal cells inside Wharton’s jelly are a type of mesenchymal stem cell, meaning they can develop into several different tissue types. In lab conditions, these cells can become bone cells, cartilage cells, and fat cells. They also express a characteristic set of surface proteins that identify them as true mesenchymal stem cells.
What makes Wharton’s jelly stem cells particularly attractive compared to other sources is their youth. Because they come from newborn tissue rather than adult tissue, they behave more like immature “pre-stem cells” with greater flexibility. Compared to stem cells harvested from adult bone marrow, Wharton’s jelly cells multiply faster, expand more readily in culture (reaching full growth in 7 to 10 days versus much longer for bone marrow cells), and show a stronger natural tendency to develop into nerve-related cell types. Bone marrow stem cells, by contrast, resist this type of nerve cell development entirely.
Low-oxygen conditions, which mimic the environment inside the body, further boost the growth of Wharton’s jelly cells while actually slowing their maturation. Bone marrow cells don’t respond the same way. These differences likely trace back to the distinct developmental origins of the two cell populations.
Current and Potential Medical Uses
Wharton’s jelly is being explored as a source material for regenerative medicine, particularly in orthopedics. Its rich concentration of growth factors and anti-inflammatory compounds makes it a candidate for treating musculoskeletal injuries and chronic joint conditions. The idea is that these biological components could reduce inflammation, ease pain, and support tissue healing in ways that conventional treatments don’t.
Beyond orthopedics, the stem cells from Wharton’s jelly produce a wide range of signaling molecules collectively called a “secretome.” These secreted factors are being studied for potential applications in wound healing, immune system modulation, and neurological repair. The cells’ strong inclination toward nerve cell development makes them especially interesting for conditions affecting the brain and spinal cord.
How Wharton’s Jelly Is Collected and Stored
Harvesting Wharton’s jelly is straightforward and painless for both parent and baby. After delivery, the umbilical cord is clamped and cut as usual. The cord is then sectioned into small pieces, rinsed, and the blood vessels are removed. The remaining gel-like tissue is minced and processed to isolate either the whole tissue or the stem cells within it.
For long-term storage, the isolated stem cells are frozen using controlled-rate freezing, a method where the temperature drops at a carefully managed pace to minimize ice crystal damage. Protective chemicals are added before freezing to keep cells viable. Studies have tested several of these protective agents, including DMSO and sugar-based solutions, to optimize how many cells survive the thawing process. This controlled approach allows Wharton’s jelly stem cells to be banked for potential future use, similar to cord blood banking.