The correlation between fetal frontal lobe development parameters and gestational week: A preliminary study

Objective To establish a reference range of developmental parameters related to the frontal lobe of normal fetuses in different gestational weeks, which can provide a basis for the evaluation of normal development of the frontal lobe and the diagnosis of suspected fetal microcephaly. Methods A prospective cross-sectional study was performed on 751 normal fetuses between 21 and 36 weeks, and the anterior-posterior diameter and transverse diameter of the frontal lobe were measured in transcerebellar plane. Linear regression analysis was performed by grouping different gestational weeks. Results Fetal anterior-posterior diameter and transverse diameter of the frontal lobe were positively correlated with gestational week with correlation coefficients 0.871 and 0.971 respectively. There was a linear relationship between gestational weeks and frontal lobe parameters, and the equations were simplified to obtain the simple correlation formula: fetal frontal lobe anterior-posterior diameter(mm)=14.5+0.7×(gestational week-21), frontal lobe transverse diameter (mm)=41+2.5×(gestational week-21). Conclusion The reference ranges of the frontal lobe anterior-posterior diameter and the frontal lobe transverse diameter of normal fetuses between 21 to 36 weeks in transcerebellar plane were established, which can provide valuable information for the evaluation of normal development of the frontal lobe and the diagnosis of suspicious fetal microcephaly. What’s already known about this topic? We currently lack a golden standard to diagnosis microcephaly and fetal frontal lobe dysplasia is a clue for prenatal diagnosis of microcephaly. What does this study add? This study presents a novel evaluation of the fetal frontal lobe to better assess brain development in the transcerebellar plane. The fetal frontal lobe developmental diameters will be useful to aid diagnosis of suspicious microcephaly and other cortical developmental disorders.