Mathematical modeling of fetal growth: II. Head cube (A), abdominal cube (B) and their ratio (A/B).
Growth of the fetal head and abdomen have been monitored by measurement of the head cube (A), the abdominal cube (B) and A/B, from 12 to 41 weeks menstrual age. Growth curves for these parameters have been determined using a specially developed growth curve model [P = c(t)k+s(t)]. R2 values of 98.0%, 96.6%, and 56.2% were obtained for A, B, and A/B, respectively. Similar results were obtained when this model was used with HC and AC data from a previous study. Variability analysis indicated a progressive increase in variability with menstrual age for both A and B while the variability of A/B decreased. The variability in the 12- to 17-week interval was significantly greater for all three parameters and the A deviation distribution was asymmetric (shifted toward negative values) after 36 weeks. Variability data were used with the growth curve models to determine standard curves for A, B and A/B.
D000005:Abdomen / Q000196:embryology*; D005314:Embryonic and Fetal Development; D005260:Female; D005333:Fetus / Q000033:anatomy & histology; D005865:Gestational Age; D006257:Head / Q000196:embryology*; D006801:Humans; D008433:Mathematics; D008954:Models, Biological; D011247:Pregnancy; D012016:Reference Values; D014463:Ultrasonography