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Umbilical artery and vein catheterisation in the neonate

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See also radiology images of UAC and UVC placement


Umbilical vessels are relatively accessible in the newborn infant, particularly the very small and very large infants. As a general rule, infants less than 1000g should have an umbilical venous catheter (UVC) inserted on day 1.

An umbilical arterial catheter (UAC) may be indicated if the infant has significant respiratory disease (ventilated or >40% oxygen), close monitoring of blood pressure is desirable, the infant is at high risk for complications even if reasonably stable on admission or is likely to require significant blood sampling over the first few days of life.

Larger infants with significant respiratory distress may also require a UAC.

Larger infants, especially sick infants, should have a UVC inserted. A double-lumen catheter may be indicated if the infant requires significant support (see Catheter Choice below").


Umbilical Venous Catheters


  • The umbilical vein is 2-3cm long and 4-5mm in diameter
  • From the umbilicus, it passes cephalad and a little to the right. It joins the left branch of the portal vein after giving off several large intrahepatic branches.
  • The ductus venosus arises from the point where the UV joins the left portal vein and bypasses the liver, joining the inferior vena cava just distal to its entry into the atrium.


  • The ideal position for a UVC is in the inferior vena cava, just outside of right atrium, at T9, which correlates to 0.5cm above the diaphragm on the lateral image.
  • Position should be verified with anteroposterior and lateral chest-and-abdominal radiographs or by echocardiography1,2
  • It can be difficult to pass the catheter through the ductus venosus. There are some manoeuvres that can assist in placement. These include:
    • Pulling the catheter back to about 4-5cm, then advancing the catheter whilst rotating the catheter clockwise
    • Passing another catheter down beside the already mal-placed catheter. The path of the second catheter may be through the ductus venosus.
    • Do not force a catheter in if there is resistance.
  • In an emergency, a UVC that remains in the portal circulation may be withdrawn until it lies in the umbilical vein. Solutions which are not isotonic can be infused through this for a short period of time until more suitable access is obtained.
  • In a resuscitation situation, it is safe to advance a UVC whilst aspirating frequently until blood return is seen. Inserting the catheter 1-2 cm beyond this point is an appropriate position for emergency use without radiographic confirmation of position3.
  • Any UVC pulled back after an X-ray should be re-X-Rayed to comfirm the correct position or confirmed by bedside clinician performed ultrasound.
  • Clearly document the line length, tip position and any adjustments made to the line after X-Ray.

Duration of use

Use of umbilical venous catheters for greater than 7 days is associated with an increased risk of central line associated bloodstream infection (CLABSI) compared with use less than 7 days4

If it is anticipated that central venous access is likely to be necessary for longer than 7 days, the UVC should be replaced with a PICC line by 7 days of age.

Catheter size5

<1500g 3.5F
>1500-3500g 5F

Catheter Choice

For infants who are term or near-term and sick enough to require central access (for example, sepsis, MAS or PPHN), a 5F double-lumen UVC should be inserted.

For infants <1000g, a 3.5F double-lumen catheter should be considered if the infant is likely to need inotropes or multiple infusions. This will be decided on an individual basis.

Insertion Distance

There are three ways to determine the insertion distance:

A.The preferred method for estimating the insertion distance for UVC is the umbilicus to nipple distance minus 1 (UN-1)11

  1. Measure the skin at the base of the stump where it connects to the anterior abdominal wall to the nipple. Subtract 1cm
  2. Remember to add the length of the umbilical stump to the distance inserted.

Umbilical artery

B. If the shoulder-to-umbilicus distance is measured, the catheter can be inserted the appropriate distance according to the graph (right)6.

  • Remember to measure from the skin at the base of the stump where it connects to the anterior abdominal wall.
  • Remember to add the length of the umbilical stump to the distance inserted.

C. Another method is to calculate the distance according to the weight of the baby. See the graph below to evaluate UVC position.

  1. An approximation of this is to use the calculation of:

UVC length (cm) = (1.5 x birthweight (kg)) + 5.55
or half the UAC length (calculated below) + 1cm7

Complications from UVC insertion include4

  • Infection
  • Thromboembolic
  • Catheter Malpositioned in the Heart and Great Vessels 
    • Pericardial effusion or cardiac tamponade
    • Cardiac arrhythmias
    • Thrombotic endocarditis
    • Haemorrhagic pulmonary infarction
    • Hydrothorax (UVC lodged in or perforating pulmonary vein)
  • Catheter Malpositioned in portal system
    • Necrotising enterocolitis
    • Perforation of colon
    • Hepatic necrosis
  • Other
    • Perforation of peritoneum
    • Obstruction of pulmonary venous return (in infants with TAPVD)
    • Plasticizer in tissues
    • Portal hypertension
    • Electrical hazard (improper grounding of equipment, or conduction of current through fluid filled catheter).
    • Visceral laceration (hepatic)

Umbilical Artery Catheters


The umbilical arteries are the direct continuation of the internal iliac arteries.

A catheter passed into an umbilical artery will usually (but not always) enter the aorta via the internal iliac artery. Its path is, therefore, initially inferior and lateral as it passes around the bladder, before turning cephalad and medial to enter the aorta

Occasionally it will pass into the femoral artery via the external iliac artery or into the gluteal arteries. The femoral artery or gluteal artery are unsuitable sites for sampling, infusion, or blood pressure monitoring.


There are two potential positions for the UAC. These are described as "high" or "low".

  • The high position is at the level of thoracic vertebral bodies T6-T9.5 This position is above the coeliac axis (T12), the superior mesenteric artery (T12-L1), and the renal arteries (L1). This position is essentially "above the diaphragm".
  • The low position is at the level of lumbar vertebral bodies L3-L4.5 This position is below the structures as above, and is above the aortic bifurcation (L4-L5). The inferior mesenteric artery arises from L3-L4. This position is essentially "above the bifurcation".

A high UAC position is associated with significantly lesser risks of clinical vascular compromise and aortic thrombus formation8. This position should be used exclusively unless a low position is the only position that can be obtained and a UAC is deemed necessary for optimum patient care.

Catheter Size5

<1200g 3.5F
>1200g 5F

Never use an 8F UAC

UAC T8Insertion Distance

The preferred method for estimating the insertion distance for the UAC is the umbilicus to nipple distance minus 1cm plus twice the distance from the umbilicus to symphysis pubis (UN-1+2 Usp)11

  • Remember to measure from the skin at the base of the stump where it connects to the anterior abdominal wall
  • Remermber to add the length of the umbilical stump to the distance inserted.
  • If you know the length of the infant, you can refer to the graph on the right which relates UAC distance to total body length.9
  • This will result in placement at approximately T8.
  • Note that of all the birth measurements, length is the least reliable.
  • Alternatively, the shoulder-to-umbilicus length can be used to estimate catheter insertion distance according to the graph on the right6
    • The average catheter distance is approximately 106% of the shoulder-to-umbilicus distance. A rule-of-thumb is shoulder-to-umbilicus distance + 2 cm allowing for the caveats below
    • Remember to measure from the skin at the base of the stump where it connects to the anterior abdominal wall.
    • Remember to add the length of the umbilical stump to the distance inserted.

UAC and UVC vs weightAnother option - and one which is particularly good if you forget to measure the shoulder-to-umbilicus length - is to calculate the insertion distance using the formula:
UAC distance (cm) = (birthweight (kg) x4) + 710.

It does no harm to insert the line a centimetre further than calculated, as the line can be pulled back slightly if needed. However, you should avoid inserting the UAC so far that it needs to be removed from the carotid or subclavian arteries.

Complications from umbilical catheterisation include5

  • Malpositioned catheter
    • Vessel perforation
    • Refractory hypoglycaemia  (if catheter tip opposite coeliac axis)
    • Peritoneal perforation
    • False aneurysm
  • Vascular accident
    • Thrombosis
    • Embolism/Infarction
    • Vasospasm
    • Loss of extremity
    • Hypertension
    • Paraplegia
    • Heart failure (from aortic thrombosis)
    • Air embolism
  • Equipment related
    • Broken catheter
    • Transection of catheter
    • Plasticizer in tissues
    • Improper grounding of electronic equipment
    • Conduction of current through fluid-filled catheter
  • Other
    • Haemorrhage
    • Infection
    • Necrotising enterocolitis
    • Intestinal necrosis or perforation
    • Transection of omphalocoele
    • Herniation of appendix through umbilical ring
    • Cotton fibre embolus
    • Wharton-jelly embolus
    • Hypernatraemia


It is the responsibility of the person inserting the catheter - doctor/NNS/NNP - to abide by the CLAB insertion checklist and to document on the CLAB insertion form the measurements, confirmation of placement via X-ray and any adjustment made ensuring correct position prior to use.

Single Umbilical Artery (SUA)

Single Umbilical Artery (SUA) is a common congenital abnormality, often also called a 2-vessel cord. Isolated SUA occurs in up to 2% of all liveborn infants.11 It may be detected antenatally, or discovered upon examination of the infant at delivery.

The majority of SUA occur as an isolated anomaly. However, SUA may be associated with other structural or chromosomal anomalies.12 The risk of a chromosomal abnormality is 10-times higher in infants with a SUA.13

The median incidence of other major abnormalities in liveborn infants with a SUA is approximately 27% (range 21.6-32.2%).11 The median incidence of occult renal abnormalities (vesicoureteric reflux, hypoplastic kidneys, absent kidney, or multicystic kidney) in otherwise normal infants with SUA in this meta-analysis was 5%.

In the absence of previously demonstrated physical abnormalities on antenatal ultrasound screening, there is little yield in obtaining investigations following delivery in infants without examination findings suggesting other anomalies.14


  1. Check if antenatal ultrasound scans demonstrated any other abnormalities 
  2. Examine the baby for dysmorphic features, abdominal masses, or cardiac disease 
  3. If no other abnormalities are found on examination, no investigations are required. 
  4. If there is suspicion of other abnormalities, appropriate investigations (imaging, karyotype) should be arranged. 


  1. Michel F, Brevaut-Malaty V, Pasquali R, Thomachot L, Vialet R, Hassid S, Nicaise C, Martin C, Panuel M. Comparions of ultrasound and X-ray in determining the position of umbilical venous catheters. Resuscitation 2012; 83: 705-709.
  2. Phelps DL, Lachman RS, Leake RD, O W. J Pediatr 1972; 81(2):336-9
  3. Lewis GC, Crapo SA, Williams JG. Critical skills and procedures in emergency medicine. Vascular access skills and procedures. Emergency Medicine Clinics of North America 2013; 31: 59-86.
  4. Butler-O'Hara M, D'Angio CT, Hoey H, Stevens TP. An evidence-based catheter bundle alters central venous catheter strategy in newborn infants. Journal of Pediatrics 2012; 160: 972-7
  5. Fletcher MA, MacDonald MG, Avery GB. Atlas of procedures in Neonatology. JB Lippincott Co, Philadelphia 1983.
  6. Dunn PM. Localisation of the umbilical catheter by post mortem measurement. Archives of Disease in Childhood 1966; 41: 69-75.
  7. Shukla H, Ferrara A. Rapid estimation of insertional length of umbilical catheters in newborns. American Journal of Diseases in Childhood 1986; 140: 786-8.
  8. Barrington KJ. Umbilical artery catheters in the newborn: effects of position of the catheter tip. Cochrane Database of Systematic Reviews 1999, Issue 1. Art. No.: CD000505. DOI: 10.1002/14651858.CD000505.
  9. Rosenfeld W, Estrada R, Jhaveri R, Salazar D, Evans H. Evaluation of graphs for insertion of umbilical artery catheters below the diaphragm. Journal of Pediatrics 1981; 98(4): 627-8.
  10. Kumar PP, Kumar CD, Nayak M, Shaikh FAR, Dusa S, Venkatalakshmi A. Umbilical artery catheter insertion length: in quest of a universal formula. Journal of Perinatology 2012; 32: 604-7.
  11. Thummala MR, Raju TNK, Langenberg P. Isolated single umbilical artery anomaliy and the risk for congenital malformations: a meta-analysis. J Pediatr Surg 1998;33:580-5. 
  12. Gossett DR, Lantz ME, Chisholm CA. Antenatal diagnosis of single umbilical artery: Is fetal echocardiography warranted? Obstet Gynecol 2002;100:903-8 
  13. Prucka S, Clemens M, Craven C, McPherson E. Single umbilical artery: What does it mean for the fetus? A case-control analysis of pathologically ascertained cases. Genet Med 2004:6(1):54-7. 
  14. Parilla BV, Tamura RK, MacGregor SN, Geibel LJ, Sabbagha RE. The clinical significance of a single umbilical artery as an isolated finding on prenatal ultrasound. Obstet Gynecol 1995;85:570-2.
  15.  Gupta AO, Peesay MR, Ramasethu J. Simple measurements to place umbilical catheters using srface anatomy. Journal of Perinatology 2015: 35(7):476-80

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Document Control

  • Date last published: 03 November 2018
  • Document type: Clinical Guideline
  • Services responsible: Neonatology
  • Owner: Newborn Services Clinical Practice Committee
  • Editor: Sarah Bellhouse
  • Review frequency: 2 years