When a Premature Baby's Brain Fluid Builds Up: Understanding the Options for Buying Time

A plain-language guide to Tang and colleagues' 2026 review of the temporary treatments used for posthemorrhagic hydrocephalus in premature babies

When a baby is born very early, one of the risks doctors watch for is bleeding inside the brain. In some of these babies, the fluid that normally cushions the brain begins to build up afterward, a condition called posthemorrhagic hydrocephalus. A 2026 review of the medical evidence, published by Tang and colleagues in the journal Frontiers in Pediatrics [1], gathers together everything doctors currently know about the temporary treatments used to relieve that fluid buildup until a baby is big and strong enough for a longer-term solution. This article explains, in everyday language, what the condition is, what the treatment choices are, and what families can expect.

What is happening inside the baby's brain

The brain floats in a clear liquid called cerebrospinal fluid, which is made continuously, circulates through spaces inside the brain called ventricles, and is then reabsorbed into the bloodstream. In a premature baby, the fragile blood vessels near these ventricles can bleed — this is known as an intraventricular hemorrhage. When that happens, the blood can block the normal drainage pathways and can also irritate and scar them, so the fluid is made faster than it can be cleared [2]. The ventricles then swell, and the growing pressure can press on and injure the delicate, still-developing brain tissue around them [3]. This is why doctors take the condition seriously and watch for it closely.

Not every baby with a brain bleed develops this problem. Overall, about 9 in 100 premature babies with a brain bleed go on to develop fluid buildup, but the chance depends heavily on how severe the bleed was — rising from roughly 1 in 100 for the mildest bleeds to about 28 in 100 for the most severe [1]. Doctors keep track using gentle bedside ultrasound scans of the head, along with regular measurements of the baby's head size, so they can catch a worsening problem early.

Why this is such a difficult decision for doctors

It helps to know that this is a genuinely hard area of medicine, and it has been for a long time. Years ago, one of the main approaches was to draw off small amounts of fluid repeatedly with spinal taps. Over time, careful studies showed that these repeated taps did not actually reduce how many babies eventually needed a permanent drainage device, and did not improve how children developed later on [4]. Doctors also came to understand that the problem is not just too much fluid, but the leftover blood itself causing irritation and scarring — which shifted thinking toward getting rid of the blood, not simply draining the fluid [2]. Even today, there is no single agreed-upon best treatment, and there are only two large, high-quality trials in the entire field. Hospitals in Europe and North America often approach the timing differently, which tells you just how much room for judgment remains [1]. Understanding this can help families make sense of why their care team weighs options carefully rather than following one fixed rule.

Some babies get better on their own

One of the most reassuring points in the review is that not every baby whose ventricles start to enlarge will need surgery. In some infants, the fluid buildup stabilizes or even improves on its own, which is exactly why doctors watch carefully with repeated scans before deciding to act — the goal is to tell apart the babies who will settle on their own from those whose fluid keeps building and who truly need help [1]. This is also why the care team may recommend waiting and watching for a period of days rather than rushing to a procedure. Waiting in this situation is not doing nothing; it is active, close monitoring designed to spare a baby an operation that would not help, while making sure no baby who needs treatment is left too long [1].

The temporary treatments, and what each involves

The review walks through the main temporary options, each of which is a kind of bridge meant to hold a baby over until a permanent solution is safe. The simplest, spinal taps, are now used only briefly and sparingly, because on their own they do not solve the problem [1][4].

When more reliable drainage is needed, surgeons can place a small, soft tube into the ventricle. One version drains fluid out to the surface temporarily; another connects the tube to a small reservoir placed just under the scalp, so nurses can gently withdraw fluid at the bedside on a schedule. A third option, often preferred for the smallest babies, channels the fluid into a natural space beneath the scalp in a fully closed system, which lowers the chance of infection [5]. Deciding between a reservoir and the under-the-scalp channel is one of the areas where the evidence is genuinely mixed: some studies favor one, others find no meaningful difference [6]. Families should also know that these devices are bridges, not cures — in one study, about 76 out of every 100 babies managed with a reservoir still went on to need a permanent shunt later [7]. A permanent shunt is a long-term device that quietly drains excess fluid from the brain to the abdomen, where the body absorbs it.

The question of timing, and treatments that remove the blood

One of the most interesting themes in the review is timing — whether stepping in earlier makes a difference. In a large European trial known as the Early versus Late Ventricular Intervention Study (ELVIS), carried out across multiple hospitals, treating babies earlier did not change how many eventually needed a permanent shunt, but it was linked to fewer children dying or having severe developmental problems by age two [8]. Other research pointed the same way, with earlier drainage linked to better thinking and learning skills years later [9]. The lesson is not that faster is always better, but that a worsening fluid buildup is something to act on thoughtfully rather than simply watch.

A newer idea is to actively wash out the old blood rather than just drain fluid. One approach, tested in a United Kingdom trial, gently rinses the ventricles and adds a medicine that helps dissolve clots. This treatment, called drainage, irrigation, and fibrinolytic therapy, is the only temporary treatment shown to improve thinking skills over the long term: ten years later, children who received it scored meaningfully higher on tests of thinking ability, and more of them were living without severe cognitive disability [10]. The catch is that it also caused more repeat bleeding, which is why it is not used routinely and is offered only at specialized centers [1][10]. Another technique uses a tiny camera to remove clots directly, and a large trial is under way to learn how well it works [1].

Keeping babies safe during treatment, and talking with the care team

Whatever device is chosen, the biggest everyday risk is infection, and this is largely preventable. Hospitals that follow strict, standardized routines for placing and accessing these devices have brought infection rates down dramatically, in some reports to nearly zero, and specially coated tubes can further lower the risk [11]. Nurses and doctors also watch closely for draining too much fluid, for changes in the body's salt balance, and for any sign of infection, checking the fluid at regular intervals. Families are an important part of this. It is completely reasonable to ask the team why a particular option was chosen, what the plan is if the fluid keeps building up, whether a permanent shunt is likely, and how the baby's development will be followed after going home. Good teams welcome these questions, because decisions here unfold over weeks and benefit from a strong partnership with parents.

What comes next

The honest summary of Tang and colleagues' review is that doctors have real options for buying time, and that early, careful attention to a worsening problem appears to protect the developing brain — but that important questions remain open [1]. Researchers are now working to learn whether stepping in earlier truly improves long-term development, which fluid-and-clot-clearing techniques are both safe and effective, and whether promising new approaches, including experimental cell-based therapies, can help repair the injured brain [12]. For families in the middle of this journey, the most reassuring message is that the care team's watchfulness — the repeated head scans, the daily measurements, the careful timing — is itself part of the treatment, aimed squarely at giving a fragile brain its best possible chance to grow.

References

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  2. Robinson S. Neonatal posthemorrhagic hydrocephalus from prematurity: pathophysiology and current treatment concepts. J Neurosurg Pediatr. 2012;9:242–258. doi:10.3171/2011.12.PEDS11136 ↩
  3. Ballabh P, de Vries LS. White matter injury in infants with intraventricular haemorrhage: mechanisms and therapies. Nat Rev Neurol. 2021;17:199–214. doi:10.1038/s41582-020-00447-8 ↩
  4. Whitelaw A, Lee-Kelland R. Repeated lumbar or ventricular punctures in newborns with intraventricular haemorrhage. Cochrane Database Syst Rev. 2017;4:CD000216. doi:10.1002/14651858.CD000216.pub2 ↩
  5. Sil K, Ghosh SK, Chatterjee S. Ventriculo-subgaleal shunts—broadening the horizons: an institutional experience. Childs Nerv Syst. 2021;37:1113–1119. doi:10.1007/s00381-020-04929-4 ↩
  6. Aljeaid R, Alharbi A, Alsuhaibani M, et al. Comparing ventricular access devices and ventriculosubgaleal shunts for posthemorrhagic ventricular dilatation: a systematic review and meta-analysis. Childs Nerv Syst. 2025;41:337. doi:10.1007/s00381-025-06998-9 ↩
  7. Park EK, Lee YH, Shim KW, Kim DS. Temporary surgical management of intraventricular hemorrhage in premature infants. J Korean Neurosurg Soc. 2023;66:274–280. doi:10.3340/jkns.2022.0265 ↩
  8. Cizmeci MN, Groenendaal F, Liem KD, et al. Randomized controlled early versus late ventricular intervention study in posthemorrhagic ventricular dilatation: outcome at 2 years. J Pediatr. 2020;226:28–35.e3. doi:10.1016/j.jpeds.2020.08.014 ↩
  9. Bassan H, Eshel R, Golan I, et al. Timing of external ventricular drainage and neurodevelopmental outcome in preterm infants with posthemorrhagic hydrocephalus. Eur J Paediatr Neurol. 2012;16:662–670. doi:10.1016/j.ejpn.2012.04.002 ↩
  10. Luyt K, Jary SL, Lea CL, et al. Drainage, irrigation and fibrinolytic therapy (DRIFT) for posthaemorrhagic ventricular dilatation: 10-year follow-up of a randomised controlled trial. Arch Dis Child Fetal Neonatal Ed. 2020;105:F466–F473. doi:10.1136/archdischild-2019-318231 ↩
  11. Cheng YK, Liu CL. Antibiotic-impregnated external ventricular drainage for posthemorrhagic hydrocephalus in low-birth-weight premature infants. Childs Nerv Syst. 2022;38:1567–1572. doi:10.1007/s00381-022-05542-3 ↩
  12. Limbrick DD, de Vries LS. New insights into the management of post-hemorrhagic hydrocephalus. Semin Perinatol. 2022;46:151597. doi:10.1016/j.semperi.2022.151597 ↩