Normal values of the fronto‐occipital relationship in fetuses between 18 and 40weeks at two maternal fetal medicine units: Bogotá, Colombia

ObjectiveTo establish nomograms for linear measurements of the frontal and occipital horns of the lateral ventricle and their relationship, in pregnant patients between 18 and 40 weeks of gestation and having attended 2 units of Maternal Fetal Medicine in Bogotá—Colombia.MethodologyA descriptive cross‐sectional study with an analytical component was carried out on pregnant patients who utilized the ultrasound services at 2 Maternal‐Fetal Medicine units in Bogotá, between 18 and 40 weeks of pregnancy who underwent measurement. From the anterior and posterior horns of the lateral ventricles, the fronto‐occipital ratio was calculated at each gestational week, and nomograms were created for each of these variables.ResultsNine hundred and seventy‐eight patients were included in the study. The distance of the frontal horns ranged between 6.9 and 51.6 mm with a mean of 19.1 ± 5.8 mm; that of the occipital horns had a measurement between 8.7 and 53 mm with a mean of 28, 1 ± 8.9 mm; on the other hand, the fronto‐occipital ratio (FOR) yielded a mean of 0.365 ± 0.067 (0.136–0.616) without bearing any relation to gestational age. The trend of normal values for the studied population is displayed, plotted in percentile curves and nomograms for each gestational age.ConclusionThe measurement of the frontal and occipital horns, and the calculation of the fronto‐occipital relationship is technically possible between 18 and 40 weeks, finding that the anterior and posterior horns have a positive linear relationship with gestational age. Contrarily, the FOR does not correlate with the gestational age, it was possible to establish a table of percentiles that allows determining the normal values for these measurements during pregnancy.