Prediction of birth weight using the Rossavik growth model: A study in a Dutch population

Abstract

Objectives: To evaluate the Rossavik growth model for predicting birth weight in a Dutch population and to evaluate growth cessation near term. Study Design: Birth weight was predicted at various ages between 38 and 42 weeks, menstrual age (MA), and at birth age in 50 normal infants using two sets of ultrasound measurements obtained before 28 weeks, MA. Predicted birth weights were compared to actual weights. The mean percentage difference was used as a measure of systematic error and the standard deviation as a measure of random error. Linear regression analysis we used to evaluate the relationship between percentage differences and birth age. To evaluate the individual growth potential, the Growth Potential Realization Index for weight (GPRIWT) was determined for each fetus. Results The predictions of 39 and 39.15 weeks, MA, were accurate without systematic error and with a random error of ±9.3%. Prediction at 38 weeks showed a statistical underestimation (mean ± SD = ‐5.8% ± 8.8), and statistical overestimations were found for predictions after 39.15 weeks and at birth age. A relationship between percentage differences and birth age was not found for predictions between 39.15 and 40 weeks, MA. These findings indicate that growth cessation occurred at 39.15 weeks, MA. Using birth weights predicted at 39.15 weeks, MA, GPRIWT were calculated. The mean GPRIWT value was not significantly different from 100% (p > 0.05), and individual GPRIWT values ranged from 84% to 114%. Conclusions The Rossavik growth model can be used to predict birth weight in a Dutch population. However, growth cessation near term appears to occur later than previously reported in other populations. © 1997 John Wiley & Sons, Inc. J Clin Ultrasound 25:235–242, 1997

Individualized growth assessment of fetal soft tissue using fractional thigh volume

“…For deliveries at 38 weeks or before, the actual birth age was used for this analysis. For subjects that delivered > 38 menstrual weeks, the birth age was defined as 38 weeks to account for growth cessation, an empirical concept derived from comparisons of predicted and measured birth characteristics after 38 weeks34–36. Predicted WT, derived from predicted head (A) and abdominal (B) cubes, and predicted CHL, derived from predicted FDL, were calculated using previously described mathematical functions37, 38.…”

Fetal growth cessation in late pregnancy: its impact on predicted size parameters used to classify small for gestational age neonates

“…GCA values of 39.5 weeks, MA, for HC, CHL and WT were found in a Dutch population by Kurniawan et al (20,21,22) In this large sample of normally growing fetuses, growth cessation was identified in all six parameters measured at birth, the GCA being 38 weeks except for the CHL [38.5 weeks]. If one focuses on the period between 38 weeks and delivery [Figure 1], the differences in Percent Difference distributions associated with assuming growth cessation at the GCA or Growth-To-Delivery [GTD] are clearly demonstrated.…”

“…Delivery was vaginal in 72% and by cesarean section in 28%. Since growth cessation has been demonstrated at 38 weeks, MA, in most previous investigations (9, 10, 13, 14, 20, 21, 22), we assumed Growth Cessation Age [GCA] of 38 weeks for our initial studies. All slopes of the linear functions relating Percent Difference [ % Diff] to Birth Age [BA] were not different from zero, except CHL [Table 1], indicating a random distribution of Percent Differences after 38 weeks.…”

“…These differences may be responsible for the results obtained in the current investigation. However, it is unlikely that differences in sample characteristics are the cause since the Houston methods have given weight estimates with similar accuracy in a Dutch population (22). …”

“…For WT, there are 8 published investigations, two using IGA procedures (22, 23), two using the scan-to-delivery interval as an independent variable in the weight estimation function (31,32) and four using methods that assume constant growth along cross-sectional size percentile lines in the 3 rd trimester (33,34,35,36). The two previous IGA studies, using measurements obtained before 28 weeks, MA and correcting for growth potential, age at delivery and growth cessation, gave similar systematic [mean: 2.3%, 1.7% vs. − 4.1%] and random errors [2 SD: 18.6%, 12.0% vs. 16.5%] prediction errors.…”