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Navel Gazing


Love them or hate them, everyone* has one. The umbilical stump is all that remains of the physical bond the neonate has with their mother.  We’ve looked at the importance of the umbilical vessels as a means of oxygenation, but the time must come to cut the cord.

The normal umbilical cord

For those of you familiar with your embryology, you might recall that the umbilical cord starts off life as the yolk stalk, containing the vitelline duct, fused to the body stalk containing a pair of umbilical arteries, a single umbilical vein and the allantois, all slathered in Wharton’s jelly and covered with amnion. The vitelline duct obliterates around week 8 of fetal life. The umbilical arteries and veins become the lateral umbilical ligaments and ligamentum teres, and the urachus becomes the median umbilical ligament.

A picture of a fresh newborn, covering her face with her hand.  The umbilical cord is clamped.

It is normally the colour of freshly cooked calamari (with a similar consistency to overcooked calamari). Still, occasionally, it may be stained green (due to the passage of meconium) or yellow (due to the presence of hyperbilirubinaemia).

A newborn with a clamp over the umbilical cord

Around one per cent of all cords have a single umbilical artery, making it one of the most common congenital abnormalities.

A cross sectional view of the umbilical cord

The cord should separate by about day 8. Still, delayed separation has been linked with an increased incidence of omphalitis and a number of immune disorders, such as leucocyte adhesion deficiency.

Immediate versus delayed cord clamping

When the baby is delivered, about a third of the fetal-placental blood remains in the placenta (around 30 ml/kg). With delayed cord clamping, the infant gains around 25-30ml/kg of blood via a placental transfusion. The majority of this transfusion occurs within a minute if the neonate is held at the level of the uterus and is almost complete in three minutes.

The evidence supporting delayed cord clamping (DCC) highlights several significant benefits for both preterm and term infants:

Improved Transitional Circulation in Preterm Infants: Delayed cord clamping is linked with better transitional circulation in preterm infants, crucial for their initial adaptation to extrauterine life​​.

Enhanced Red Blood Cell Volume and Decreased Need for Transfusions: DCC contributes to a better establishment of red blood cell volume, which is vital for carrying oxygen throughout the body. This can reduce the need for blood transfusions in these newborns​​.

Lower Incidence of Necrotizing Enterocolitis and Intraventricular Hemorrhage: Preterm infants who undergo DCC have a lower incidence of necrotizing enterocolitis and intraventricular hemorrhage, both of which are serious complications​​.

Improvement in Hemoglobin and Hematocrit Levels in Term Infants: For term and near-term infants, DCC has been shown to improve hemoglobin and hematocrit levels, which are crucial for adequate oxygen transport in the blood​​.

Potential Neurodevelopmental Benefits: Evidence suggests that DCC may promote improved neurodevelopment in infants, which is a critical aspect of their early growth and development​​​​.

Increased Iron Status for Up to 6 Months: Delayed cord clamping can improve an infant’s iron status for up to six months after birth. This is particularly important, as iron is a critical component for brain development and overall growth​​.

Positive Effects on Blood Pressure and Fewer Transfusions Required: The practice has been linked to higher blood pressure in infants and a reduced need for transfusions, contributing to better neonatal health​​.

Increase in Placental Transfusion, Red Blood Cells, and Neonatal Blood Volume: DCC results in an increase in placental transfusion, a 60% increase in red blood cells (RBCs), and a 30% increase in neonatal blood volume. This increased blood volume provides a crucial buffer for newborns as they adapt to life outside the womb​​.

Decreased Risk of Iron Deficiency Anemia: One of the significant advantages of DCC is the decreased risk of iron deficiency anaemia, a common concern in early infancy

A recent Cochrane review suggested that delayed cord clamping (by 1 to 3 minutes) is “likely to be beneficial as long as access to treatment for jaundice requiring phototherapy is available“. This review suggested no difference in adverse events such as severe maternal postpartum haemorrhage, low Apgar scores or worsening neonatal mortality figures compared to immediate clamping. There was a correlation between increased birth weight (by about 100g) and increased haemoglobin with a concomitant increased risk of needing phototherapy for jaundice.

WHO recommends delaying clamping for at least one minute unless the baby is not breathing spontaneously and requires positive pressure ventilation. This holds true in both the developed and developing settings. The benefits of delayed clamping outweigh the risk of maternal-fetal transmission of HIV.

Animal studies have also shown that immediate cord clamping might lead to a reduction in cardiac output. Once the cord has been clamped, right ventricular volume drops, leading to decreased RV output by around 50%. There is also an increase in LV afterload due to the lack of low-resistance placental circulation.

What about “milking” the cord?

Milking refers to the practice of actively expressing blood from the cord. Small volume studies have been performed on preterm infants and suggest milking leads to a higher haemoglobin concentration (than delayed clamping alone) and reduced need for transfusion, as well as a shorter duration of mechanical ventilator support.

Problems with the umbilical stump

Delayed cord separation

Delayed cord separation, often occurring beyond the typical 1-3 week period after birth, can be a sign of underlying medical conditions, including Leukocyte Adhesion Deficiency (LAD). LAD is a rare, inherited immunodeficiency disorder affecting the immune system’s ability to fight infection. It’s characterized by leukocyte defects, which impair their adhesion and migration, crucial for combating infections.

In LAD, delayed umbilical cord separation is often accompanied by severe, recurrent infections from early life. These infections are usually caused by bacteria and can affect various parts of the body, including the skin, mucous membranes, and respiratory tract. Due to the impaired function of leukocytes, the infections in LAD patients are often severe and can be life-threatening.

There are three types of LAD:

  1. LAD-1: The most common form, caused by a defect in the CD18 gene leading to impaired expression of β2 integrins. It’s characterized by severe infections and delayed wound healing.
  2. LAD-2: A rare form caused by a defect in the SLC35C1 gene, affecting the fucosylation of selectins and selectin ligands. It presents with milder infections compared to LAD-1.
  3. LAD-3: The rarest form, with symptoms similar to LAD-1, but also includes bleeding problems due to platelet dysfunction.

Diagnosis of LAD typically involves blood tests to analyze leukocyte function and genetic testing to identify specific gene mutations. Early diagnosis is crucial for managing the condition effectively.

Treatment options are primarily supportive, focusing on preventing and treating infections promptly. Antibiotic prophylaxis and aggressive treatment of infections when they occur are common approaches. In severe cases, hematopoietic stem cell transplantation (HSCT) may be considered to correct the underlying defect in leukocyte function.


Omphalitis is an infection around the umbilical stump that first manifests as redness and erythema and can progress to life-threatening sepsis. The devitalised stump provides a fertile medium for bacterial growth. Common infective agents include Staph. aureus, Streptococcus spp. and E. coli spp. Infection is linked to handling and poor hygiene, and a rash of cases in the 1950s led to the regular local anti-bacterial treatment of the stump.

Risk factors for omphalitis

  • Maternal – prolonged rupture of the membranes, maternal infection, amnionitis
  • Delivery – non-sterile birth, inappropriate cord care
  • Neonatal – low birth weight, delayed cord separation, leukocyte adhesion deficiency, neonatal alloimmune neutropaenia

In developed countries, the incidence of infection is low in the region of 0.7%, so “dry cord care” is recommended. Allowing the stump to air dry speeds up the separation process. In low-income countries, the incidence is much higher, up to 6%, so this standard does not apply. One study in Nepal found that using 4% aqueous chlorhexidine decreased the incidence of omphalitis by 75% and mortality by 24% compared to the Westernized ideal of “dry cord care”. Better hygiene also decreases the incidence of neonatal tetanus. When an education initiative stopped the Kenyan Maasai from routinely smearing the umbilical stump with cattle dung, the death rate from tetanus dropped from 82 per 1,000 to 0.75 per 1,000 infants.

Whilst mild cases may respond to good hygiene, it can progress to necrotizing fasciitis of the abdominal wall if left unchecked. Because of this, most cases require admission, close monitoring and treatment with parenteral antibiotics.

Umbilical hernia

An umbilical hernia is one of the more common umbilical disorders and is seen in around 10% of Caucasian babies. They are also more common in premature infants and those with trisomy 21. Like all true hernias, they may contain peritoneal fluid, pre-peritoneal fat, intestine or omentum protruding through a fascial defect.

An umbilcal hernia

The hernia is normally painless, but as it is more obvious when the child screams and cries, parents might bring the child to a healthcare provider concerned that something serious is happening. The defect in the deep fascia of the abdominal wall usually heals up over time, with the majority closing spontaneously over the first three years of life. The larger the defect, the less likely that spontaneous closure occurs. Those defects less than 1.5cm in diameter are often left until the age of four to six years to close on their own. Incarceration of peritoneal contents is exceedingly rare.

Risk factors for umbilical hernias:

  • Premature or low birth-weight infants
  • Children of African descent
  • Beckwith-Wiedeman
  • Trisomy 21
  • Marfan’s syndrome<

Why is there an increase in the incidence in African children? A Nigerian study found them in 91% of children under 6 and 64% of 6 to 9-year-olds. Nutrition may be a factor, as only 1.3% of children in the higher socio-economic groups had them. This has also been seen to be true in adults.

Umbilical granuloma

Umbilical granulomata are small (less than 1cm) lumps of umbilical tissue that remain following the separation of the cord and are one of the more common causes of a persistent “wet umbilicus“. Small ones are typically pedunculated masses of moist, raw-looking tissue and can be treated with topical application of silver nitrate. Larger ones might require formal resection.

An umbilcal granuloma

Vitelline duct remnants

Vitelline duct remnants join the terminal ileum to the umbilicus. This omphalo-mesenteric remnant may persist as the famous Meckel’s diverticulum affects 2% of the population. See what Pediatric EM Morsels has to say on the matter.

Urachal remnants

Urachal remnants connect the dome of the bladder to the anterior abdominal wall. During fetal development, this patent tube allows the free drainage of urine but becomes obliterated by solid tissue to become the median umbilical ligament. Occasionally, it fails to close, creating a patent urachus, a urachal sinus or a cyst. A urachal cyst may only appear later in life with symptoms that mimic appendicitis. Ultrasound may help make the diagnosis. They should all be referred to a paediatric surgeon for further assessment.

‘Innies’ versus ‘Outies’

I had always thought that it had something to do with how the cord was cut or clamped but that cannot be true so I fired up Dr Google to find an answer – it’s not the sort of thing you can find in PubMed. Apparently, outies are due to a little extra scar tissue that affects about 10% of the population.

*So, who doesn’t have a belly button and why?

Selected references

Poenaru D. Disorders of the umbilicus in infants and children: A consensus statement of the Canadian Association of Paediatric Surgeons. Paediatrics & child health. 2001 Jul 1;6(6):312-3.

O’Donnell KA, Glick PL, Caty MG. Pediatric umbilical problems. Pediatric Clinics of North America. 1998 Aug 1;45(4):791-9.

Imdad A, Bautista RMM, Senen KAA, Uy MEV, Mantaring III JB, Bhutta ZA. Umbilical cord antiseptics for preventing sepsis and death among newborns. Cochrane Database of Systematic Reviews 2013, Issue 5. Art. No.: CD008635. DOI: 10.1002/14651858.CD008635.pub2.

Onal E, Turan O, Karabulut R, Hirfanoglu I, Turkyilmaz C, Sonmez K, Türkyılmaz Z, Kapısız A, Basaklar AC. Where should the Normal Position of the Umbilicus be in the Neonate?. European Journal of pediatric surgery. 2010 Sep;20(05):339-40.

Onal E, Turan O, Karabulut R, Hirfanoglu I, Turkyilmaz C, Sonmez K, Türkyılmaz Z, Kapısız A, Basaklar AC. Where should the Normal Position of the Umbilicus be in the Neonate?. European Journal of pediatric surgery. 2010 Sep;20(05):339-40.

Meegan ME, Conroy RM, and Lengeny SO, et al.  Effect on neonatal tetanus mortality after a culturally-based health promotion programme.  Lancet 2001; 358:640-41

Uba AF, Igun GO, Kidmas AT, and Chirdan LB.  Prevalence of umbilical hernia in a private school admission-seeking Nigerian children. Niger. Postgrad. Med. J. 2004; 11:255-257

Raju, Tonse N. K., and Nalini Singal. “OPTIMAL TIMING FOR CLAMPING THE UMBILICAL CORD AFTER BIRTH.” Clinics in perinatology 39.4 (2012): 10.1016/j.clp.2012.09.006. PMC. Web. 10 Dec. 2016.

Rabe H, Jewison A, Alvarez RF, Crook D, Stilton D, Bradley R, Holden D, Brighton Perinatal Study Group. Milking compared with delayed cord clamping to increase placental transfusion in preterm neonates: a randomized controlled trial. Obstetrics & Gynecology. 2011 Feb 1;117(2, Part 1):205-11.

Rabe H, Reynolds G, Diaz-Rossello J. A systematic review and meta-analysis of a brief delay in clamping the umbilical cord of preterm infants. Neonatology. 2007 Sep 21;93(2):138-44.

McDonald SJ, Middleton P, Dowswell T, Morris PS. Effect of timing of umbilical cord clamping of term infants on maternal and neonatal outcomes. Cochrane Database of Systematic Reviews 2013, Issue 7. Art. No.: CD004074. DOI: 10.1002/14651858.CD004074.pub3 [/toggle]



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