Umbilical cord length and its associated factors and birth outcomes among singleton deliveries at Dilla University Referral Hospital, Southern Ethiopia: a hospital-based cross-sectional study

Inside the womb, a single, coiled rope connects a developing baby to the life-support system of the placenta. This is the umbilical cord, a vital highway made of blood vessels wrapped in a protective, jelly-like substance. Its job is simple but absolute: it carries oxygen and nutrients from the mother to the growing fetus and carries away waste. For decades, doctors have known that this connection is not just a passive tube; its length, thickness, and how it twists can tell a story about how the pregnancy is progressing. While a cord that is too short might struggle to stretch during birth, one that is too long can become tangled around the baby's neck or body. Yet, for many regions of the world, including parts of Ethiopia, the specific details of how long these cords usually are, what makes them grow longer or shorter, and how their size relates to the health of the baby at birth have remained largely a mystery.

A team of researchers set out to fill this gap at Dilla University Referral Hospital in Southern Ethiopia. They focused on a specific group of mothers who gave birth to a single baby, excluding twins or triplets to keep the data clear. Over three months in 2025, they carefully measured the umbilical cords of 257 newborns immediately after delivery. The process was precise: once the cord was clamped and cut, the team measured the segment attached to the baby and the segment attached to the placenta, adding them together to get the total length. They did not stop at just measuring the rope; they also weighed the placenta, recorded the baby's weight, noted the mother's health history, and tracked how the baby fared in the first few minutes of life. By gathering all these details, they hoped to see if the length of the cord was linked to the size of the baby, the health of the placenta, or the outcome of the birth.

The researchers found that the average cord length in this group was 56.21 centimeters, with most cords falling between 43 and 70 centimeters. When they looked deeper into the data, a clear pattern emerged regarding what drives the length of this connection. The length of the cord was not random; it grew in step with the baby and the placenta. Specifically, heavier placentas and heavier babies were linked to longer cords. For every additional kilogram a baby weighed, the cord tended to be about 2.17 centimeters longer. Similarly, for every 100 grams the placenta weighed, the cord grew by roughly 1.2 centimeters. The timing of the birth also mattered significantly. Babies born before their full term had noticeably shorter cords, averaging about 51 centimeters, compared to full-term babies who averaged 56.6 centimeters. This suggests that the cord grows steadily as the pregnancy progresses, and a shorter cord can sometimes be a sign that the baby arrived early.

Beyond the physical measurements, the study revealed that the length of the cord was linked to how the baby was doing right after birth. The researchers discovered that longer cords were associated with a higher likelihood of the baby having a lower score on the Apgar test, a quick check of a newborn's health done five minutes after birth. This might seem counterintuitive, but the researchers suggest it is not because a long cord is inherently bad. Instead, a longer rope has more material that can get wrapped around the baby or tangled during the final stages of labor, potentially causing temporary stress. Conversely, shorter cords were linked to a higher risk of the placenta staying inside the mother after birth and a higher risk of stillbirth. In the cases of stillbirth, the babies had cords that were significantly shorter than average, averaging just over 51 centimeters. This indicates that an unusually short cord might be a marker for a pregnancy that faced difficulties before the baby was even born.

The study also looked at whether the cord length affected other common birth complications, such as the need for a cesarean section, prolonged labor, or the baby needing admission to a special care unit. In these areas, the researchers found no clear link. The length of the cord did not seem to predict whether a mother would have a difficult labor or whether the baby would need extra medical support immediately after birth. This is an important distinction, as it suggests that while cord length is a useful piece of information, it is not a crystal ball for every possible problem. The findings also showed that factors like the mother's age, whether she smoked, or her level of education did not have a strong, independent effect on how long the cord grew. The growth of the cord appeared to be driven primarily by the physical development of the baby and the placenta itself.

Ultimately, this research provides a clearer picture of what is normal for umbilical cords in Southern Ethiopia. It confirms that the cord is a dynamic part of the pregnancy that grows alongside the baby and the placenta. While the study cannot prove that the cord length causes these outcomes, the connections it found are strong enough to suggest that measuring the cord is valuable. The authors recommend that doctors in the region consider recording the length of the cord as part of their routine check after a baby is born, especially if the baby is stillborn or seems unwell. This simple measurement could offer a small but important clue about the health of the pregnancy. However, the researchers caution that the cord length should never be looked at in isolation; it is just one piece of a much larger puzzle involving the mother, the baby, and the placenta. To fully understand how to use this information to improve care, larger studies involving more hospitals and more babies will be needed in the future.