Umbilical Cord: An Evidence-Based Guide for Patients

The umbilical cord is a temporary structure that connects a developing baby to the placenta during pregnancy. It carries oxygen and nutrients to the baby, removes waste products, and is carefully checked before and after birth because some cord-related conditions can affect pregnancy or newborn care.

Overview: what the umbilical cord is and why it matters

The umbilical cord is a flexible, tube-like structure that connects the baby to the placenta during pregnancy. In simple terms, it acts as the baby’s lifeline: it delivers oxygen and nutrients from the placenta and carries waste products away from the baby so the mother’s body can process them. This exchange supports normal growth and development until birth.

A typical umbilical cord contains three blood vessels: one vein and two arteries. The vein carries oxygen-rich, nutrient-rich blood toward the baby, while the arteries carry blood back toward the placenta. These vessels are surrounded by a cushioning substance called Wharton’s jelly, which helps protect them from pressure and kinking as the baby moves.

The cord begins to form early in pregnancy and continues to develop as the baby grows. Its length and appearance can vary, and many normal differences do not cause problems. Doctors and sonographers routinely assess the placenta and cord during prenatal care because their structure can provide useful information about the health of the pregnancy.

After delivery, the cord is clamped and cut because the baby no longer needs the placental circulation. A small stump remains on the baby’s belly button area, then dries and naturally falls off over the following days to weeks. Understanding this normal process can help parents feel more confident about newborn care.

How the umbilical cord works during pregnancy

The placenta and umbilical cord work as a single system. The placenta attaches to the wall of the uterus and exchanges oxygen, nutrients, and waste between the mother’s blood supply and the baby’s blood supply. The umbilical cord is the route that allows this exchange to reach the baby efficiently.

Unlike the baby’s lungs and digestive system, which are still developing before birth, the placenta performs many of the tasks needed to support life in the womb. Through the umbilical vein, the baby receives oxygen and essential nutrients such as glucose, amino acids, fats, vitamins, and minerals. Through the umbilical arteries, carbon dioxide and other waste products return to the placenta.

The cord also protects this circulation mechanically. Wharton’s jelly helps prevent the vessels from being compressed too easily. In addition, the cord is naturally coiled, which may add flexibility and resilience as the baby changes position. These design features are part of why the cord usually functions well even with normal fetal movement.

Doctors may assess blood flow in the cord when there are concerns about fetal growth, placental function, or pregnancy complications. In selected situations, ultrasound and Doppler studies help clinicians understand whether the baby is receiving adequate support in the womb.

Normal features and common variations

Many parents hear about the umbilical cord during routine ultrasound, often when the placenta, baby’s growth, and blood flow are being checked. A normal cord usually has three vessels and a central or slightly off-center attachment to the placenta. The cord may appear long or short, thick or thin, and still be completely healthy.

Some variations are found incidentally and may not cause major problems, while others call for closer follow-up. For example, a single umbilical artery means the cord has two vessels instead of three. This finding can occur on its own or sometimes be associated with other developmental concerns, so the care team may recommend a detailed ultrasound and ongoing monitoring.

Another variation is where the cord inserts into the placenta. Marginal insertion means the cord attaches near the placental edge, while velamentous insertion means the vessels travel through membranes before reaching the placenta. These patterns may increase the chance of bleeding or reduced protection of the vessels and may require careful obstetric planning.

Parents may also hear terms such as nuchal cord, true knot, or cord prolapse. A nuchal cord means the cord is looped around the baby’s neck, which is relatively common and often does not cause harm. A true knot or cord prolapse is less common and can be more significant because it may affect blood flow and needs prompt medical assessment.

Potential umbilical cord problems and risk factors

Most pregnancies progress without serious cord-related complications, but some conditions deserve attention because they can affect the baby’s oxygen supply or the safety of labor. Problems can include cord compression, abnormal vessel number, abnormal placental insertion, cysts, knots, prolapse, and issues related to placental blood flow. These are usually identified through prenatal imaging, fetal monitoring, or events during labor.

Cord prolapse happens when the umbilical cord slips into the birth canal ahead of the baby after the membranes rupture. Because the cord can become compressed, this is considered an obstetric emergency. Abnormal fetal heart rate patterns may also suggest that the cord is being compressed during labor, although not every change means a dangerous condition is present.

Some risk factors increase the likelihood of cord-related issues. These may include multiple pregnancy, too much amniotic fluid, abnormal fetal position, preterm rupture of membranes, placental abnormalities, or a cord that appears unusually long. However, many cord problems occur without a clear preventable cause, and routine prenatal care remains the best way to identify them early.

Cord findings may also overlap with placental concerns or fetal growth concerns. When a doctor suspects reduced placental support, further evaluation for conditions such as placenta previa or restricted growth may be needed. In some pregnancies, specialists use targeted ultrasound or perinatology care to guide monitoring and delivery planning.

How doctors evaluate the umbilical cord

The umbilical cord is usually assessed as part of standard prenatal care. Ultrasound can show the number of cord vessels, how the cord inserts into the placenta, and whether the baby’s growth appears appropriate for gestational age. This information helps clinicians decide whether the pregnancy needs routine follow-up or more frequent observation.

If there is a concern about blood flow, Doppler ultrasound may be used to evaluate circulation in the umbilical vessels. This test can provide important clues about placental function and the baby’s well-being, especially in pregnancies complicated by high blood pressure, diabetes, or suspected growth restriction. Depending on the findings, doctors may also recommend nonstress tests or biophysical profiles.

During labor, the healthcare team monitors the baby’s heart rate for signs that could suggest cord compression or reduced oxygen delivery. Changes in the tracing do not automatically mean there is a severe problem, but they do help guide decisions about positioning, oxygenation support for the mother, and whether a faster delivery may be needed.

After birth, the cord and placenta are examined as part of routine maternity and newborn care. In some cases, the placenta may be sent for pathology review if there were pregnancy complications, infection concerns, or questions about the baby’s condition at birth. Imaging such as ultrasound remains the main prenatal tool for assessing cord anatomy and function.

Care after birth: the cord stump, healing, and possible concerns

Once the baby is born, the umbilical cord is clamped and cut, leaving a short stump attached at the belly button area. The stump usually changes from yellowish to brown or black as it dries. In most newborns, it falls off on its own within 1 to 3 weeks, and a small amount of dried blood can be normal during this process.

Routine cord stump care is simple. Parents are usually advised to keep the area clean and dry, fold the diaper below the stump if possible, and avoid pulling on it even when it looks loose. Sponge bathing may be recommended until the stump falls off and the skin has healed. Unless a clinician specifically advises it, topical products are often unnecessary.

Possible concerns include redness spreading onto the surrounding skin, foul-smelling discharge, swelling, persistent moisture, or bleeding that does not stop with gentle pressure. These signs can suggest infection or delayed healing and should be discussed with a doctor. A small amount of pink tissue after the stump falls off may be an umbilical granuloma, which is usually benign but may need treatment.

Some babies also develop an umbilical hernia, where tissue bulges through a weak area near the belly button. This is different from the cord stump itself and often improves as the child grows, though it should still be assessed during pediatric visits. If there are concerns about newborn healing or structural issues, a pediatric or neonatology team may be involved.

Prevention, monitoring, and self-care during pregnancy

There is no proven way for a parent to prevent most umbilical cord variations, because they usually develop as part of the pregnancy rather than from something a person did or did not do. The most helpful step is attending regular prenatal visits so that the placenta, baby’s growth, and cord can be checked at appropriate times. Following medical advice for any pregnancy condition, such as high blood pressure or diabetes, also supports placental and fetal health.

Monitoring the baby’s movements later in pregnancy can be useful, especially if a clinician has advised paying attention to movement patterns. A noticeable reduction in movement should not be ignored. While many causes are not serious, changes in activity can sometimes be linked to issues that need prompt evaluation.

General pregnancy self-care also matters. This includes eating a balanced diet, staying hydrated, avoiding smoking and non-prescribed substances, taking prenatal vitamins as recommended, and reporting symptoms such as vaginal bleeding, fluid leakage, severe abdominal pain, or regular contractions before term. These steps do not guarantee prevention of cord problems, but they support safer pregnancy monitoring overall.

For people with high-risk pregnancies, care may involve more frequent scans or specialist follow-up. Near the end of the care journey, Acibadem International’s multidisciplinary specialists in JCI-accredited hospitals diagnose and treat pregnancy and newborn conditions for international patients when advanced evaluation is needed.

When to seek medical care

Medical advice should be sought during pregnancy if there is reduced or absent fetal movement, vaginal bleeding, sudden leakage of fluid, severe abdominal pain, contractions before the expected time, or any symptom that feels clearly different from usual. These symptoms do not always mean there is an umbilical cord problem, but they should be evaluated without delay. If a doctor has already identified a cord or placental abnormality, following the recommended monitoring plan is especially important.

Urgent care is needed if labor starts and something appears at the vaginal opening after the waters break, because this could suggest cord prolapse. Parents should also seek medical care for a newborn if the cord stump area becomes red, swollen, warm, foul-smelling, or persistently bleeding. Fever, poor feeding, unusual sleepiness, or signs that the baby seems unwell are also reasons to contact a healthcare professional promptly.

Most umbilical cord findings can be managed safely with timely assessment and appropriate follow-up. Because every pregnancy and newborn is different, personalized advice from an obstetrician, midwife, pediatrician, or family doctor remains the safest guide.

Frequently asked questions

What is the main function of the umbilical cord?

The umbilical cord connects the baby to the placenta during pregnancy. Its main role is to carry oxygen and nutrients to the baby and return waste products to the placenta for removal.

How many blood vessels are normally in the umbilical cord?

A normal umbilical cord usually has three blood vessels: one vein and two arteries. The vein brings oxygen and nutrients to the baby, while the arteries carry blood back toward the placenta.

Is a cord around the baby's neck always dangerous?

Not always. A nuchal cord, which means the cord is looped around the baby's neck, is relatively common and often does not cause harm. Doctors monitor the baby during pregnancy and labor to make sure blood flow and heart rate remain reassuring.

How long does it take for the umbilical cord stump to fall off?

In most newborns, the stump falls off within 1 to 3 weeks after birth. Keeping it clean and dry usually helps normal healing, and parents should avoid pulling it off.

What signs of umbilical cord stump infection should parents watch for?

Parents should watch for redness spreading onto the skin, swelling, warmth, foul-smelling discharge, or bleeding that does not stop easily. If the baby has fever, poor feeding, or seems unwell, prompt medical advice is important.

Can umbilical cord problems be seen on ultrasound?

Many can. Ultrasound can often show the number of vessels, where the cord attaches to the placenta, and whether blood flow appears normal. Sometimes additional Doppler studies or repeat scans are recommended.

References

• World Health Organization
• American College of Obstetricians and Gynecologists
• Centers for Disease Control and Prevention
• American Academy of Pediatrics
• National Institute of Child Health and Human Development

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.