Screening for detection of intra-uterine growth retardation by means of ultrasound.

Abstract

In a two-stage ultrasound screening program the gestational age was assessed by measurement of the fetal crown-rump length in early pregnancy. At an adjusted gestational age between 32 and 35 completed weeks the biparietal diameter, the abdominal circumference, the abdominal area and the ratio between fetal head area and abdominal area were estimated by means of ultrasound measurement. 'Acute' fetal weight was estimated by calculations from biparietal diameter and abdominal diameters. Percentile curves were constructed for these parameters and cut-off limits were tested for the predictability of intra-uterine growth retardation of the fetus. The abdominal circumference and area estimations were equally good for the detection of intra-uterine growth retardation. The biparietal diameter alone is of limited value for the detection of intra-uterine growth retardation but the combination with abdominal diameters in 'acute' fetal weight estimation can well be used. The ratio between the skull and abdominal areas seems to be of little use for the detection of intra-uterine growth retardation of two reasons: difficulty in measurement and low sensitivity. We consider that the assessment of gestational age in early pregnancy is a necessity both for the identification of suspected IUGR by means of ultrasound and the diagnosis of IUGR by measurement of fetal weight at birth. It is concluded that if the gestational age has been assessed by crown-rump length measurement in early pregnancy, a single estimation of the fetal abdominal circumference between 32 and 35 completed gestational weeks and a cut-off limit at the 15th percentile offers a detection rate of about 90% of the growth retarded infants.