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Intra-uterine long bone growth in small-for-gestational-age infants
J Palacios1, S Rodríguez, J I Rodríguez
1Department of Pathology, La Paz Hospital, Madrid, Spain.
Insights
Small-for-gestational-age (SGA) infants show reduced long bone mass due to altered bone modeling and remodeling. This impacts cortical bone development, affecting diaphyseal and medullary diameters in newborns.
Area of Science:
- Pediatric Bone Biology
- Neonatal Development
- Skeletal Growth
Background:
- Intrauterine bone development is crucial for neonatal health.
- Small-for-gestational-age (SGA) infants exhibit distinct growth patterns.
- Understanding bone modeling and remodeling in SGA neonates is essential.
Purpose of the Study:
- To investigate intrauterine bone modeling and remodeling in SGA infants.
- To compare long bone development in SGA versus appropriate-for-gestational-age (AGA) newborns.
- To identify specific skeletal parameters affected in SGA infants.
Main Methods:
- Postmortem X-ray analysis of long bones (femur, tibia, humerus) in SGA infants (n=34).
- Measurement of bone length, diaphyseal and medullary diameters, cortical thickness, and cortical area.
- Comparison with a control group of AGA infants (n=146).
Main Results:
- SGA infants had significantly lower bone length and cortical bone mass compared to AGA infants.
- Reduced cortical bone mass in SGA infants resulted from decreased diaphyseal and increased medullary diameters.
- Even when weight-matched, SGA infants showed lower cortical bone mass due to larger medullary diameters.
Conclusions:
- Reduced cortical bone mass in SGA infants is a complex process involving both bone modeling and remodeling.
- Altered diaphyseal and medullary dimensions contribute to diminished bone mass in SGA neonates.
- Findings highlight specific skeletal growth disturbances in SGA newborns requiring further investigation.
Abstract:
To better understand the intra-uterine bone modelling and remodelling process in small-for-gestational-age (SGA) newborn infants, long bone growth was studied using postmortem X-ray films in a group of such infants (n = 34). Bone length, diaphyseal diameter, medullary diameter, cortical thickness, cortical area, the Barnett-Nordin index, and the percentage of cortical area were determined in femur, tibia, and humerus. A separate group of appropriate-for-gestational-age (AGA) newborn infants (n = 146) was used as controls. Length and cortical bone mass in all three bones were significantly lower in SGA infants than in AGA infants. Decreased cortical bone mass in SGA infants was the result of decreased diaphyseal diameters and increased medullary diameters. Similar results were obtained when SGA infants were subclassified as preterm and term and compared with the control group of AGA infants. Bone lengths and diaphyseal diameters in SGA infants did not differ from those observed in a weight-matched control group of AGA infants although the latter were younger by 4 weeks' gestation. However, the cortical bone mass was lower than in the control group because of the relative greater medullary diameters in all three long bones in the SGA infants. Our present results indicate that reduced cortical bone mass in SGA infants is a mixed growth modelling and remodelling dependent process.