2026, Number 2
Analysis of acute complications associated with intrauterine growth restriction in neonates weighing less than 2,500 g
Full text
10.35366/122610
Language: English/Spanish [Versión en español]
References: 11
Page: 98-101
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ABSTRACT
The purpose of this study was to analyze the complications of intrauterine growth restriction, both moderate and severe, in newborns weighing less than 2.5 kg. A retrospective study was carried out with a review of clinical records from the Hospital Angeles Pedregal of newborns weighing less than 2.5 kg, over a period of three years. The following data were collected: gestational age, weight, and sex. These data were classified according to the degree of intrauterine restriction. The frequency of IUR in the study population was analyzed, as well as the presence of acute complications, Hypothermia, the need for oxygen administration, multifactorial hyperbilirubinemia, and sepsis. An analysis of the results was carried out using descriptive and analytical statistics, using means, standard deviation, and the p-test. The results were found from 101 patients studied: Hypothermia (21.2%), with severe IUGR, and (11.4%) with moderate IUGR. Hypoglycemia (7%), oxygen administration to 20 patients (8%) had severe IUGR, and 29% moderate IUGR, hyperbilirubinemia in two patients, and one patient had early neonatal sepsis. The acute complications of intrauterine growth restriction are diverse and can have a significant impact on perinatal morbidity and mortality; those found were respiratory, metabolic, and infectious.ABBREVIATIONS:
- EFW = estimated fetal weight
- IUGR = intrauterine growth restriction
- NICU = neonatal intensive care unit
INTRODUCTION
Intrauterine growth restriction (IUGR) is a fetal growth rate that is less than normal for a baby's growth potential due to genetic or environmental factors.1 It is generally classified into moderate and severe, according to anthropometric and hemodynamic parameters. Moderate IUGR refers to fetos with an estimated weight below the 10th percentile for gestational age, while severe IUGR is defined as an estimated fetal weight below the 3rd percentile, frequently accompanied by alterations in Doppler flows, such as absent or reverse diastolic flow in the umbilical artery.2
The acute complications of IUGR in term newborns are diverse and can affect multiple organ systems. According to medical literature, newborns with IUGR have a higher risk of experiencing perinatal asphyxia and neonatal adaptation problems, which include respiratory difficulties3 such as meconium aspiration syndrome, persistent pulmonary hypertension, and pulmonary hemorrhage.4,5 Furthermore, these neonates may present instability in glucose regulation, which can lead to hypoglycemia, as well as thermal instability and polycythemia.4,5
It has also been documented that neonates with IUGR have an increased risk of developing metabolic and hematological complications, such as hypocalcemia and coagulation disorders.5,6 Although hemostatic alterations are common, such as thrombocytopenia and prolonged coagulation tests, they do not always correlate with clinical manifestations of bleeding or thrombosis.6
It is important to highlight that IUGR is also associated with complications such as hypoxic-ischemic encephalopathy and sepsis, as well as an increased risk of admission to the neonatal intensive care unit (NICU).7 Early identification and proper management of these neonates are crucial to minimize acute complications and improve long-term outcomes.
MATERIAL AND METHODS
Term patients diagnosed with IUGR weighing less than 2,500 grams were studied, which were categorized as moderate (between the 3rd and 10th percentile) and/or severe (percentile < 3), and a group of infants older than 36 weeks with a weight less than 2,500 grams as a control group.
A retrospective study was conducted with a review of clinical records from the Hospital Angeles Pedregal of newborns weighing less than 2,500 grams over a three-year period.
The following data were collected: gestational age, weight, and sex, and they were classified according to the degree of intrauterine restriction.
The frequency of IUGR in the studied population was analyzed.
The presence of acute complications was determined, such as hypothermia, defined by body temperature < 36 °C or temperature between 36-36.5 °C in the first hour of life; hypoglycemia, when glucose was less than 47 mg/dL; need for supplemental oxygen administration to maintain transcutaneous saturation between 92 and 96%; and multifactorial hyperbilirubinemia treated with phototherapy for two days.
An analysis of the results was carried out using descriptive and analytical statistics, utilizing means, standard deviation, and the p-test.
RESULTS
A total of 101 patients were found, of whom 38 were males and 63 were females. Of these, 61 presented moderate IUGR and 33 severe IUGR; seven had an adequate gestational age.
Hypothermia was found in the first hour of life, with less than 36 °C in 16/101 patients, of whom 7/33 (21.2%) were diagnosed with severe IUGR, 7/61 (11.4%) with moderate IUGR, and 2/7 (28%) with adequate weight for gestational age.
Cases of 52 patients with a temperature below 36.4 °C at one hour of life were recorded; it was observed that only two patients had a temperature below 36 °C at one hour of life, one with severe IUGR and one with moderate IUGR; 50 patients presented a temperature between 36-36.5 °C, of whom 15/50 (30%) were diagnosed with severe IUGR and 35/50 (65%) with moderate IUGR.
Of the total number of patients, 7/101 (7%) presented hypoglycemia, of whom 3/33 had severe IUGR (9%) and 4/61 moderate IUGR (6.5%).
Supplemental oxygen administration was required for 20 patients, of whom 2/33 (8%) had severe IUGR and 18/61 (29%) moderate IUGR; two of the 18 patients with moderate IUGR who required oxygen were admitted to intermediate care due to transient tachypnea of the newborn, which was managed with ventilatory support using an oxygen hood.
Two patients presented multifactorial hyperbilirubinemia, treated with phototherapy for two days, of whom one had severe IUGR and one moderate IUGR; one patient presented early neonatal sepsis, treated in intermediate care for seven days with a dual antibiotic regimen.
DISCUSSION
In comparison between gestational age and IUGR, those born with a lower gestational age and the same weight presented hypothermia more than newborns with IUGR.
At one hour of life, temperature usually rises; however, 52/101 (50%) of the patients considered in this study presented between 36 and 36.5 °C, which is classically considered hypothermia. The question is whether it should be considered pathological or if it is a normal process.
In the Nepalese context, normal temperature parameters in newborns can be influenced by environmental factors and postnatal care practices. According to medical literature, it has been observed that in Nepal, 85% of patients present temperatures below 36 °C at 2 hours of life, and nearly 50% maintain temperatures below this threshold at 24 hours, without presenting alterations. A study conducted at the main maternity hospital in Kathmandu found that neonates' axillary temperature reached 36 °C after an average of 6.4 hours postpartum, indicating prolonged cold exposure.1 Another observational study, conducted at the same hospital, reported that 85% of newborns had temperatures below 36 °C at 2 hours of life, and nearly 50% maintained temperatures below this threshold at 24 hours.8
IUGR presents a risk of hypoglycemia of less than 10%, regardless of whether it is severe or moderate.
Although this study did not find the explanation, everything seems to indicate that the need for supplemental oxygen is more frequent in moderate IUGR than in severe cases.
This study also does not allow determining the risk of sepsis and hyperbilirubinemia.
Furthermore, it has the limitation of being a retrospective study with a limited number of patients; it is necessary to conduct prospective and multicenter studies to achieve greater reliability of the results.
In the context of intrauterine growth restriction (IUGR) in term newborns, acute complications vary significantly between those with moderate and severe restriction.
According to medical literature, neonates with an estimated fetal weight (EFW) below the 3rd percentile, considered as severe IUGR, present a higher incidence of neonatal complications compared to those with an EFW between the 3rd and 9th percentile, considered as moderate IUGR.9
A relevant study found that 57.5% of neonates with an EFW < 3rd percentile experienced an adverse composite neonatal outcome, compared to 20.9% with an abdominal circumference < 3rd percentile but an EFW between the third and ninth percentiles.1 This composite outcome includes complications such as NICU admission, necrotizing enterocolitis, sepsis, respiratory distress syndrome, mechanical ventilation, retinopathy of prematurity, seizures, intraventricular hemorrhage, fetal death, or death before hospital discharge.10
These findings underline the importance of IUGR severity in predicting neonatal complications, suggesting that neonates with severe IUGR have a significantly higher risk of neonatal morbidity compared to those with moderate IUGR.10
For severe IUGR, complications are more serious and frequent. One study found that 34% of neonates with severe IUGR presented respiratory distress syndrome, 30% developed sepsis, and 13% suffered retinopathy of prematurity.1 Additionally, pulmonary hypertension is a significant complication, with a reported incidence of 33.3% in neonates with IUGR.11 The need for NICU admission is also more common in cases of severe IUGR, with 44.76% of neonates requiring intensive care.9
CONCLUSIONS
In newborns weighing less than 2.5 kg, IUGR was associated with the early onset of thermal, metabolic, respiratory, and infectious complications, confirming high neonatal vulnerability from the first hour of life. Mild hypothermia was frequent, and according to the study's findings, temperatures between 36 and 36.5 °C can be interpreted as part of an early thermal adaptation process rather than an isolated pathological event, especially in settings with environmental limitations. Hypoglycemia occurred in a low proportion, so while clinically relevant, it did not constitute a predominant complication in this cohort. The need for supplemental oxygen evidenced clinically significant respiratory compromise, highlighting the importance of close respiratory surveillance from birth. Overall, the results fulfill the study's objective by demonstrating that IUGR, regardless of its severity, is associated with early neonatal morbidity that requires timely identification and management.
Events of hyperbilirubinemia and early neonatal sepsis were infrequent, limiting the ability to establish firm associations, although confirming the diversity of potential complications in neonates with IUGR. These findings underscore the need to individualize the interpretation of neonatal temperature and to strengthen thermoprotection strategies in low birth weight newborns. Likewise, they support the implementation of systematic metabolic and respiratory monitoring protocols. The evidence obtained should be further explored through prospective, controlled, and multicenter studies to confirm the findings and define evidence-based interventions to improve neonatal outcomes.
REFERENCES
AFFILIATIONS
1 Hospital Angeles Pedregal. Facultad Mexicana de Medicina de la Universidad La Salle. México.
2 Sociedad Hidalguense de Neonatología. ORCID: 0009-0001-6935-3133.
3 ORCID: 0000-0003-1562-8872.
If you wish to consult the supplementary data for this article, please contact editorial.actamedica@saludangeles.mx
CORRESPONDENCE
Dra. Carolina Samperio Pérez. Correo electrónico: carolinasamperioperez@gmail.comReceived: 2024-11-22. Accepted: 2025-03-13.