Influence of the interval between time points on individual fetal growth curve standards derived from Rossavik models and two ultrasound scans before 26 weeks, menstrual age

✍ Scribed by Nicolas V. Simon; Russell L. Deter; John S. Levisky; Theodor Stefos; David M. Shearer

• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 535 KB
• Volume: 17
• Category: Article
• ISSN: 0091-2751
• DOI: 10.1002/jcu.1870170403

✦ Synopsis

We studied the influence of the interval between the two scans used before 26 weeks' menstrual age to generate individual fetal growth curve standards utilizing the Rossavik growth model: P = c(tIk + '(') (model specification functions previously reported). Intervals of 3 weeks to 12 weeks were suitable for predicting the growth of the abdominal and head circumferences and femur diaphysis length in individual fetuses. However, large systematic and random errors were found with intervals less than 5 weeks for three-dimensional parameters such as the head and abdominal cubes and estimated fetal weight. In addition, the data suggest that the systematic errors for these latter parameters may increase with intervals of 10 weeks or more. Overall, optimal individual fetal growth curve standards were best generated from two scans before 26 weeks' menstrual age separated by 5 weeks to 9 weeks. Indexing Words: Fetal growth Rossavik growth model Intrauterine growth retardation Rossavik and Deter introduced a new method of fetal growth evaluation where various fetal anatomic parameters are compared in the last 14 weeks of menstrual age to individual fetal growth curve standards determined from scans at two time points before 26 weeks' menstrual age.'-'' The general expression of the Rossavik growth model is P = c(tIk + s't', and the method of growth curve standard specifications has been described at length in prior publications.'-12 Although these authors intuitively recommended intervals of at least 6 weeks between time point^,^ the influence of the interval on the gen-From the