A Bedside Scanner Instead of an X-Ray: Getting Newborn Umbilical Lines in the Right Place

Two 2025 studies looked at whether ultrasound during placement makes umbilical catheters safer for sick and premature babies

Why the position of a thin plastic tube matters so much

When a baby is admitted to a neonatal intensive care unit very sick or very premature, one of the first things the team does is place a soft catheter into a blood vessel in the umbilical cord stump. It is a painless way to give medicines, nutrition, and fluids, and to draw blood without repeated needle sticks. But the tube has to end up in exactly the right spot inside the body, and for decades doctors have had to place it partly by guesswork and then check with an X-ray. Two studies published in 2025 asked whether using a bedside ultrasound scanner instead would work better.

The first was a randomized trial at a hospital in Kaohsiung, Taiwan, in which 150 newborns were assigned by chance to have their catheter position checked either by X-ray or by ultrasound [1]. The second was a review that gathered together every comparable study published worldwide and weighed the evidence as a whole [2]. They reach mostly the same conclusion, with one important difference in how confident they are about it.

The problem doctors have been living with

To understand why this matters, it helps to know how umbilical catheters have traditionally been placed. The umbilical cord contains blood vessels that stay open for the first days after birth, offering a ready-made route into a newborn's circulation. But the doctor cannot see inside the baby while threading the tube. Since 1986, most units have used a formula based on the baby's birth weight to estimate how far to push the catheter in [3]. The formula is a good average, but babies are not averages — a particular baby's liver and blood vessels may be shaped slightly differently, and the tube ends up too far in, not far enough, or off to the side.

That happens often enough to matter. When researchers combined results from more than 14,000 babies, they found that about 13 in every 100 umbilical catheters were linked to some kind of problem, and roughly 4 in every 10 of those problems were simply the tube being in the wrong place [4]. Most of the time a misplaced tube is spotted and pulled back without harm. Occasionally it is not, and fluid ends up leaking into the liver — a serious complication that has been documented repeatedly in the medical literature [5]. Reviews of complications in large intensive care units have consistently traced them back to two things: a tube in the wrong position, and a tube left in for too long [6].

The traditional way of checking is an X-ray, which produces a flat, two-dimensional picture of a three-dimensional problem. Doctors noticed as far back as 2012 that ultrasound and X-ray sometimes disagreed about where the tube was [7], and a later analysis comparing the two methods found that X-rays agree with ultrasound only about 82% of the time on one of the two measures of accuracy the researchers used [8]. X-rays also only show a single moment, and catheters can drift over the following days, especially in premature babies [9]. And every X-ray means waiting: the film has to be ordered, a machine wheeled in, the picture taken and read. During that wait, a baby who needs medicine through the line has to wait too.

What the Taiwanese trial found

Between May 2022 and December 2024, doctors in Taiwan divided newborns needing umbilical catheters into three groups [1]. One group had the traditional approach: formula, tape, X-ray. The other two groups had the position checked by ultrasound while the tube was being placed, so it could be adjusted immediately; these two groups differed only in the type of dressing used to hold the tube in place. In total, 140 babies were included in the final results.

The differences were striking. With X-ray, it took an average of about 102 minutes to confirm the tube was in the right place. With ultrasound, it took about 24 minutes in one group and about 12 minutes in the other. The tube ended up in the wrong place in half of the X-ray group (50%) compared with roughly one in five of the ultrasound groups (21.7% and 18.2%). Bacteria were found growing on the catheter tip in 30% of the X-ray group, compared with 10.9% and 6.8% of the ultrasound groups. Most importantly, four babies in the X-ray group (8%) developed a bloodstream infection linked to the line — and none of the 90 babies in the two ultrasound groups did.

The reason appears to be simple and physical. In the X-ray group, half of the catheters had to be un-taped, repositioned, and re-secured after the picture came back. Every time a sterile dressing is opened and a tube is handled, there is another opportunity for bacteria to get in. The type of dressing itself made no measurable difference at all — the two ultrasound groups had almost identical results despite using different dressings. What mattered was getting the tube right the first time.

What the worldwide review adds — and why it is more cautious

The second 2025 publication took a different approach [2]. Rather than running a new study, its authors searched four major medical databases and found six studies comparing ultrasound-guided placement with the traditional blind method, involving 863 babies in total across wealthy, middle-income, and lower-income countries. They then rated how trustworthy the combined evidence was.

Their findings agreed with the Taiwanese trial on the main points: ultrasound roughly halved the chance of a misplaced tube, and shortened the procedure by about six minutes on average. But they rated the certainty of this evidence as "low," meaning future research could still change the picture. On infection they found no clear benefit — but only one small study in their collection had measured it at all. That gap is exactly what the Taiwanese trial began to fill, which is why the two publications are best read together rather than as rivals.

Other trials give a sense of what different units achieve. Two of the three randomized trials in the review were run in lower-income countries and still found that ultrasound reduced misplacement [10], and a separate randomized trial found correct placement rose from about 20% to 64% for one type of umbilical catheter and from 33% to 84% for the other [11]. Those are real improvements, but they also show the technique does not make placement perfect — a lot depends on how experienced the person holding the scanner is.

What this means for your baby

If your baby needs an umbilical catheter, it is entirely reasonable to ask how your unit checks the position. Some units now use ultrasound routinely, some are training their staff, and some still rely on X-rays; all three are recognised approaches, and an X-ray-based unit is not doing something wrong. What the 2025 evidence suggests is that ultrasound, where available and where staff are trained in it, tends to get the line usable sooner, with fewer adjustments and fewer repeat X-rays.

That last point is worth knowing about. Babies in intensive care can receive anywhere from zero to 159 X-rays during a single admission, and the smallest and most premature babies tend to receive the most [12]. Each individual X-ray involves a very small amount of radiation, and none of these studies found harm from them — but reducing unnecessary exposure is a goal every neonatal unit shares.

It is also worth keeping the infection question in proportion. Bloodstream infections from central lines are a genuine and serious risk in intensive care, and rates vary widely between hospitals — one survey of neonatal units found an eight-fold difference between the best and worst [13]. Ultrasound is one of many things units do to reduce that risk, alongside hand hygiene, sterile technique, and removing lines as soon as they are no longer needed. It is a helpful tool, not a guarantee.

What researchers are working on next

The main open question is whether the infection benefit seen in Taiwan holds up. Four babies is a small number to build a conclusion on, and the researchers who wrote the worldwide review calculated that a properly convincing study would need to enrol several hundred babies across multiple hospitals. That trial has not yet been done, and it is the single most useful thing the field could produce next.

A second area of work is training. Detailed step-by-step protocols for using ultrasound to guide catheters in newborns already exist [14], and units that adopt them have published their before-and-after results [15]. What is not yet settled is how much supervised practice a doctor or nurse needs before their results match those of an expert. A third area is using ultrasound not just at placement but repeatedly afterwards, to catch a catheter that has drifted out of position in the days that follow [16].

None of this changes the fundamental picture, which is a hopeful one. A procedure that has been performed half-blind since the 1960s is becoming one that clinicians can watch as they do it. The evidence is not yet complete, but it points consistently in one direction: seeing is better than guessing and checking.

References

  1. Lin YJ, Liu YC, Huang HC, et al. Echocardiographic Determination of Umbilical Catheter Tip Location Mitigates Complications: A Randomized, Controlled Trial. Children (Basel). 2025;12(11):1509. doi:10.3390/children12111509 ↩
  2. Anne RP, Rahiman EA, Aradhya AS. Real-time ultrasound for umbilical venous catheter insertion in neonates — a systematic review and meta-analysis. The Ultrasound Journal. 2025;17:4. doi:10.1186/s13089-025-00406-8 ↩
  3. Shukla H, Ferrara A. Rapid estimation of insertional length of umbilical catheters in newborns. Am J Dis Child. 1986;140:786–788. doi:10.1001/archpedi.1986.02140220068034 ↩
  4. Gibson K, Sharp R, Ullman A, et al. Adverse events associated with umbilical catheters: a systematic review and meta-analysis. J Perinatol. 2021;41:2505–2512. doi:10.1038/s41372-021-01147-x ↩
  5. Grizelj R, Vukovic J, Bojanic K, et al. Severe liver injury while using umbilical venous catheter: case series and literature review. Am J Perinatol. 2014;31:965–974. doi:10.1055/s-0034-1370346 ↩
  6. Levit OL, Shabanova V, Bizzarro MJ. Umbilical catheter-associated complications in a level IV neonatal intensive care unit. J Perinatol. 2020;40:573–580. doi:10.1038/s41372-019-0579-3 ↩
  7. Michel F, Brevaut-Malaty V, Pasquali R, et al. Comparison of ultrasound and X-ray in determining the position of umbilical venous catheters. Resuscitation. 2012;83:705–709. doi:10.1016/j.resuscitation.2011.11.026 ↩
  8. Cao J, Zhang Y, Yin Y, Liu Y. Accuracy of chest radiography compared to ultrasound for positioning the umbilical venous catheter in neonates: a meta-analysis and systematic review. J Vasc Access. 2023;24:1051–1060. doi:10.1177/11297298211046755 ↩
  9. Franta J, Harabor A, Soraisham AS. Ultrasound assessment of umbilical venous catheter migration in preterm infants: a prospective study. Arch Dis Child Fetal Neonatal Ed. 2017;102:F251–F255. doi:10.1136/archdischild-2016-311202 ↩
  10. Kaur A, Manerkar S, Patra S, et al. Ultrasound-guided umbilical venous catheter insertion to reduce rate of catheter tip malposition in neonates: a randomized, controlled trial. Indian J Pediatr. 2022;89:1093–1098. doi:10.1007/s12098-022-04295-w ↩
  11. Ponin L, Ruangkit C, Ruangwattanapaisarn N, Nuntnarumit P. Real-time ultrasound to assess the umbilical catheter position in neonates: a randomized, controlled trial. J Perinatol. 2025;45:235–241. doi:10.1038/s41372-024-02128-6 ↩
  12. Gislason-Lee AJ. Patient X-ray exposure and ALARA in the neonatal intensive care unit: global patterns. Pediatr Neonatol. 2021;62:3–10. doi:10.1016/j.pedneo.2020.10.009 ↩
  13. Jansen SJ, Broer SDL, Hemels MAC, et al. Central-line-associated bloodstream infection burden among Dutch neonatal intensive care units. J Hosp Infect. 2024;144:20–27. doi:10.1016/j.jhin.2023.11.020 ↩
  14. Barone G, Pittiruti M, Biasucci DG, et al. Neo-ECHOTIP: a structured protocol for ultrasound-based tip navigation and tip location during placement of central venous access devices in neonates. J Vasc Access. 2022;23:679–688. doi:10.1177/11297298211007703 ↩
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  16. Xie HQ, Xie CX, Liao JF, et al. Point-of-care ultrasound for monitoring catheter tip location during umbilical vein catheterization in neonates: a prospective study. Front Pediatr. 2023;11:1225087. doi:10.3389/fped.2023.1225087 ↩