FETAL GROWTH VELOCITY - KINETIC, CLINICAL, AND BIOLOGICAL ASPECTS

With the aim of determining fetal growth kinetics, prenatal data were analysed which had been longitudinally collected in the framework of a perinatal growth survey. The sample comprised 238 singleton normal pr egnancies, selected in Genoa and Turin (between 1987 and 1990), and re peatedly assessed by ultrasound scans (five to nine per pregnancy). Fi ve morphometric traits were considered: BPD (biparietal diameter), HC (head circumference), FDL (femur diaphysis length) and AC (abdomen cir cumference). Growth rate seemed to increase in the early part of the s econd trimester, and decrease subsequently: velocity peaks were steepe r and earlier for head diameters and circumference (about 18 weeks) th an for femur length (20 weeks) and abdomen circumference (22 weeks). V elocity standards were traced using a longitudinal two-stage linear mo del: this ensures unbiased description of the shape of the growth curv e, even when growth kinetics are asynchronous, and efficient estimatio n of the outer centiles - the most useful for diagnostic purposes.