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[Neonatal anthropometry and early differentiations in embryo-fetal growth]
Insights
Biologic variability in fetal size emerges early in pregnancy, with distinct growth patterns identifiable by 12 weeks gestational age. These early anthropometric differences persist throughout pregnancy, suggesting early genetic influence on fetal growth.
Area of Science:
- Obstetrics and Gynecology
- Fetal Development
- Neonatal Research
Context:
- Biologic variability in fetal size increases with gestational age.
- Early fetal growth patterns and influencing factors remain debated.
- Transversal studies may underestimate early fetal growth variability.
Purpose:
- To evaluate embryo-fetal growth differentiation using a longitudinal study.
- To correlate early fetal growth with neonatal anthropometric measurements.
- To identify the timing of fetal growth differentiation.
Summary:
- A longitudinal study analyzed 238 neonates from low-risk pregnancies.
- Fetal growth velocity curves showed differences by 12 weeks gestational age.
- Anthropometric differences observed early persist until term, indicating early genetic potential expression.
Impact:
- Demonstrates that anthropometric differences are present by the first trimester.
- Suggests a very early expression of genetic potential for individual fetal growth.
- Highlights the importance of early fetal assessment in understanding growth trajectories.
Abstract:
It is well known that the biologic variability in fetal size increases as pregnancy advances, although the embryonal and early fetal growth patterns as well as how early and how much the genetic, hormonal and environmental variables play a role in its modulation are still debated. It is accepted that growth in the first trimester of pregnancy is relatively uniform, with a minimal biologic variability; this variability may be underestimated, because the transversal studies do not permit the identification of the growth pattern. The aim of this work is to evaluate, by means of a longitudinal study, the time of embryo-fetal growth differentiation related at neonatal anthropometric measurements. We evaluated 238 neonates (123 female; 115 male) delivered at term after low risk, uncomplicated pregnancies. The subjects were divided into three tertles (low, mid and high) according to birth weight, length and head circumference. For each tertle, distance curves, velocity curves, and rate of increase were calculated by using respectively fetal abdominal circumference (for birth weight), fetal femural length (for neonatal length) and fetal head circumference (for neonatal circumference). The distance curves showed clear differences among the tertles only in the second period of pregnancy, whereas the velocity curves showed clear differences among tertles already in the first 12 weeks. The value of growth rates were similar for all the variables during the entire time considered. This study shows that the anthropometric differences between newborn subgroups exist already at the end of the first trimester of pregnancy and, in physiological conditions, until the end of pregnancy. The anthropometric differences observed early in our study, at twelve weeks of gestational age, are still present at the end of pregnancy and let us suppose a very early expression of the genetic potential for individual growth.