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Early 72-Hour Weight Loss and Short-Term Neonatal Outcomes in Very Low Birth Weight Infants: A Prospective Cohort Study

This prospective cohort study of 98 very low birth weight infants suggests that greater postnatal weight loss (>10%) within the first 72 hours is associated with reduced surfactant requirements and numerically lower rates of major morbidities without increasing mortality, indicating that such weight loss may serve as a marker of successful neonatal adaptation rather than an adverse outcome.

Original authors: Elif Yaşar, Elif Ozalkaya, Sevilay Topcuoglu, Emre Dincer, Selim Sancak, Güner Karatekin

Published 2026-08-26

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CC BY 4.0

Original authors: Elif Yaşar, Elif Ozalkaya, Sevilay Topcuoglu, Emre Dincer, Selim Sancak, Güner Karatekin

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

Every baby born early faces a delicate balancing act the moment they leave the womb. Inside the mother, they are surrounded by fluid, and their bodies are filled with extra water that they do not need once they begin breathing air. For a healthy baby born at full term, shedding this extra water happens naturally and without fuss. But for infants born very small and very early, this process is far more complicated. Their kidneys are immature, their skin lets water escape easily, and their bodies struggle to manage the shift from a fluid-filled environment to the dry air of a hospital room. Doctors must walk a tightrope: giving enough fluid to keep the baby's organs working, but not so much that the baby becomes swollen and their lungs or heart suffer. For years, medical teams have watched the scale closely, wondering if the amount of weight a baby loses in the first few days tells them something important about how well the baby is adapting to life outside the womb.

A team of researchers at a specialized hospital in Turkey decided to investigate this question directly. They focused on the most vulnerable group of all: babies born weighing less than 1,250 grams, which is roughly the weight of a large loaf of bread. These tiny infants are at high risk for serious complications, and the way doctors manage their fluids in the first three days of life is a critical part of their care. The researchers followed 98 of these babies, tracking exactly how much weight each one lost during the first 72 hours. They divided the infants into three groups based on their weight loss: those who lost less than 5 percent, those who lost between 5 and 10 percent, and those who lost more than 10 percent. The goal was to see if losing more weight meant the babies were in danger, or if it might actually signal that their bodies were adjusting successfully.

The results challenged a common worry among medical staff. Many doctors fear that if a baby loses too much weight, it means the baby is dehydrated or not getting enough fluids, which could lead to kidney problems or unstable blood pressure. However, this study found that the babies who lost the most weight—more than 10 percent—were not in worse shape than the others. In fact, these babies received the highest amount of fluids during the first three days, yet they still lost more weight. This happened because their bodies were shedding water through their skin and urine at a faster rate, a sign that their systems were actively clearing out the extra fluid they did not need. Despite receiving more liquid, these infants had lower levels of a substance in their blood called creatinine, which is often used to check kidney function, suggesting their kidneys were handling the fluid load well.

Perhaps the most surprising finding was that the babies with the greatest weight loss did not suffer more from the serious complications that often plague premature infants. The researchers looked for signs of trouble such as bleeding in the brain, a heart condition where a blood vessel fails to close, or the need for strong medicines to support blood pressure. While the numbers were not large enough to prove a statistical difference, the pattern was clear and consistent. The group that lost more than 10 percent of their body weight had the lowest rates of these problems. They were less likely to need medication to close a heart vessel, less likely to experience brain bleeding, and less likely to need drugs to support their circulation. They also required fewer doses of a special medicine called surfactant, which helps the lungs expand, suggesting their lungs were clearing fluid more effectively.

The study did not find any evidence that losing more weight was harmful. There was no increase in death rates, infections, or feeding problems among the babies who lost the most weight. The researchers concluded that early weight loss should not be viewed as a sign of failure or dehydration, but rather as a natural part of a baby's body adjusting to the new world. It appears that when a very small baby loses weight quickly in the first few days, it may actually be a positive sign that their body is successfully getting rid of the extra water it was born with. This does not mean doctors should try to make babies lose weight, but it suggests that if a baby loses a significant amount, it is not necessarily a cause for alarm. Instead, it might be a reassuring indicator that the baby's internal systems are working as they should, adapting to life with a healthy and necessary contraction of fluid. The findings suggest that the best approach is to watch the baby's overall condition and adjust fluids carefully, rather than fearing a specific amount of weight loss.

Technical Summary: Early 72-Hour Weight Loss and Short-Term Neonatal Outcomes in Very Low Birth Weight Infants

Problem Statement
Early postnatal weight loss in very low birth weight (VLBW) infants (birth weight <1250 g) is a critical indicator of the transition from intrauterine to extrauterine life, reflecting the interplay between extracellular fluid contraction, renal maturation, and insensible water loss. While excessive fluid administration has been linked to adverse outcomes such as patent ductus arteriosus (PDA), intraventricular hemorrhage (IVH), and bronchopulmonary dysplasia (BPD), there is no consensus on the optimal range of physiological weight loss during the first 72 hours. Specifically, the clinical significance of early weight loss in infants weighing less than 1250 g remains incompletely understood, with limited data determining whether greater weight loss indicates successful adaptation or adverse dehydration and instability.

Methodology
This was a prospective cohort study conducted at a tertiary neonatal intensive care unit in Istanbul, Türkiye, between February 2023 and February 2024.

Population: 98 preterm infants with birth weights below 1250 g were enrolled. Infants with major congenital anomalies, chromosomal abnormalities, complex congenital heart disease, or death within the first 72 hours were excluded.
Grouping: Infants were categorized into three groups based on percentage weight loss during the first 72 hours:
- Group 1: <5% weight loss (or weight gain) ( $n=48$ ).
- Group 2: 5–10% weight loss ( $n=36$ ).
- Group 3: >10% weight loss ( $n=14$ ).
Data Collection: Maternal and neonatal demographics, cumulative fluid intake, urine output, and laboratory parameters (serum electrolytes, creatinine, blood gases) were recorded.
Outcomes: The study compared respiratory outcomes (RDS, surfactant use, ventilation), cardiovascular outcomes (PDA, inotropic support), major morbidities (IVH, NEC, sepsis), and mortality across the three groups.
Statistical Analysis: Comparisons utilized ANOVA or Kruskal–Wallis tests for continuous variables and Chi-square or Fisher's exact tests for categorical variables, with significance set at $p < 0.05$ .

Key Results

Fluid Management and Physiology: Infants in the >10% weight loss group received significantly higher cumulative fluid volumes during the first 72 hours compared to the other groups ( $105.8 \pm 17.1$ mL/kg/day vs. lower volumes in other groups; $p < 0.001$ ). Despite higher fluid intake, this group exhibited significantly lower serum creatinine concentrations ( $0.7 \pm 0.3$ mg/dL; $p = 0.018$ ).
Respiratory Outcomes: There were no significant differences in the incidence of respiratory distress syndrome (RDS), respiratory support requirements, or weaning success. However, infants with >10% weight loss required significantly fewer surfactant doses ( $0.9 \pm 0.3$ ) compared to the <5% group ( $1.5 \pm 0.9$ ; $p = 0.042$ ).
Cardiovascular and Morbidity Outcomes: No statistically significant differences were found in the rates of PDA, IVH, inotropic support, feeding intolerance, sepsis, or mortality among the groups.
- Numerical Trends: Despite the lack of statistical significance (likely due to sample size), the >10% weight loss group consistently demonstrated numerically lower rates of PDA (28.6% vs. ~50% in other groups), IVH (21.4% vs. ~30–37%), and inotropic support (28.6% vs. ~39–42%).
Mortality: 7-day mortality was comparable across all groups (ranging from 2.8% to 7.1%; $p = 0.782$ ).

Significance and Claims
The authors conclude that greater early postnatal weight loss (specifically >10%) in VLBW infants is not associated with increased mortality or major short-term morbidities. Instead, the findings suggest that early postnatal weight loss may serve as a clinically useful marker of successful neonatal adaptation rather than an indicator of adverse outcomes.

Key claims include:

Adaptation Marker: The observation that infants with greater weight loss received higher fluid volumes yet experienced lower creatinine levels and fewer surfactant doses suggests that weight loss reflects effective physiological fluid contraction and pulmonary fluid clearance rather than fluid deficit.
Cardiovascular Stability: The consistent numerical reduction in PDA, IVH, and inotropic support among infants with greater weight loss supports the hypothesis that appropriate extracellular fluid contraction facilitates cardiovascular adaptation and stabilizes cerebral perfusion.
Clinical Interpretation: The study advocates for interpreting weight loss within the context of individualized fluid management and overall clinical status, rather than targeting a specific predefined weight loss threshold.

The authors explicitly state that while the numerical trends are promising, the study is limited by its single-center design and small sample size, particularly in the >10% group. They do not claim that inducing weight loss is a therapeutic goal, but rather that observing it may indicate a favorable adaptive process. They call for larger, multicenter studies to validate these findings and determine the optimal range of early postnatal weight loss.

Technical Summary: Early 72-Hour Weight Loss and Short-Term Neonatal Outcomes in Very Low Birth Weight Infants

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