B.P.D. Growth Standards in the Rhesus Monkey
Serial sonar fetal cenhalometry was performed on sixty-seven pregnant monkeys, (Macaca Mulatta) with known breeding dates. It became apparent that the biparietal diameter growth could be followed along four percentile divisions; namely, the 10th–24th, 25th–49th, 50th–74th, and 75th–90th. It is shown, that under normal conditions, fetuses initially positioned in any one of these divions will continue to grow within the confines of that same percentile range. This biological phenomenon has not been previously reported. It is important because it results in a predictable normal cranial growth rate, which leads to a more precise separation of the growth retarded fetus. It may well be that a similar growth pattern exists in the human fetus. If this extrapolation is true, the detection of intrauterine growth retardation by sonography will be markedly enhanced.