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Prenatal growth in symmetric and asymmetric small-for-gestational-age infants
1Department of Community Medicine and General Practice, University of Trondheim, Norway.
Insights
Growth retardation in both symmetric and asymmetric small-for-gestational-age (SGA) infants appears to begin in the second trimester, not differing by type. No brain sparing effect was observed in asymmetric SGA infants.
Area of Science:
- Perinatology
- Fetal Development
- Neonatal Research
Background:
- Small-for-gestational-age (SGA) infants exhibit growth restriction.
- SGA infants are classified as symmetric or asymmetric.
- The timing of growth retardation onset and brain sparing effects in SGA subtypes are not fully understood.
Purpose of the Study:
- To test the hypothesis of differing growth retardation onset times in symmetric versus asymmetric SGA infants.
- To investigate the presence of a brain sparing effect in asymmetric SGA infants compared to symmetric SGA infants.
Main Methods:
- Prenatal ultrasonic measurements (fetal abdominal diameter, femur length, biparietal diameter) were taken at weeks 17, 25, 33, and 37 of gestation.
- Infants were categorized into symmetric SGA, asymmetric SGA, and non-SGA groups (n=474).
- Cross-sectional and longitudinal growth curve analyses were performed.
Main Results:
- Growth retardation in both symmetric and asymmetric SGA infants was found to commence during the second trimester.
- Growth patterns for both SGA groups were similar from the second trimester until birth.
- No evidence of a brain sparing effect was detected in asymmetric SGA infants relative to symmetric SGA infants.
Conclusions:
- The study did not support the hypothesis of distinct temporal onsets for growth retardation in symmetric and asymmetric SGA infants.
- Findings indicate similar intrauterine growth trajectories for both SGA subtypes starting in the second trimester.
- The absence of a brain sparing effect in asymmetric SGA infants was noted.
Abstract:
We tested the hypothesis that growth retardation in symmetric small-for-gestational-age (SGA) infants may start in the first trimester of pregnancy, whereas in asymmetric SGA infants, it may start in the third trimester. We also examined if there may be a brain sparing effect in asymmetric SGA infants. Infants were classified as symmetric or asymmetric SGA infants, and 474 non-SGA infants. Intrauterine growth was assessed by prenatal ultrasonic measurements of fetal abdominal diameter, femur length and biparietal diameter at week 17, 25, 33 and 37 of gestation. Cross-sectional data as well as longitudinal growth curves suggested that growth retardation in both SGA groups started in the second trimester, and followed similar patterns until birth. Thus, our results did not support the hypothesis that symmetric and asymmetric growth retardation is associated with clear temporal differences in growth, and we found no sign of brain sparing in asymmetric compared to symmetric SGA infants.