Diagnosis of Intrauterine Growth Retardation by Serial Ultrasonic Cephalometry

Abstract

The ultrasonic technique provided a new and sensitive method for the early detection of retarded intrauterine growth (IUGR). The incidence and the intrauterine development of fetuses with retarded growth of the biparietal diameter (BPD) were investigated. The accordance between retarded BPD growth and IUGR, judged from endpoint observation (reduced fetal size at birth) was established. In a routine screening program, 1317 pregnant women were examined by ultrasound twice for cephalometry. The BPD determinations were performed in the 19th and 32nd postmenstrual wk. Normal increment of the BPD during the 19th-32nd wk interval was 40 mm (90% confidence limits; 37 and 43 mm). Retarded BPD growth was defined as an increase less than 37 mm, which is equal to the growth of less than 5% of the fetuses. Of the fetuses 6.3% had a retarded BPD growth. The further development of this group (Group S) was carefully monitored. The risk of preterm delivery was increased (26%) as was the perinatal mortality (5.9%). Infant weight, length and head circumference at birth were below the 10th centile for dates in 45, 44 and 36%, respectively. The mean birth-weight of Group S was 750 g less than normal. Group S did not reveal any correlation between the degree of the BPD deviation and the outcome of pregnancy or the infant size. The growth retardations detectable at the 32nd wk were in general uniform, i.e., head and body dimensions were equally small. This was true also for the placental weight in those pregnancies that were terminated before the 38th wk, but thereafter, there was a tendency for the fetus to have outgrown its placenta. By only 2 measurements of the BPD it is possible to diagnose a large risk group of pregnancies with not only a high proportion of preterm deliveries but also infants with low birth weight. The new approach to fetal growth considers birth-weight and the time of onset of the growth retardation.