Diagnosis of Intrauterine Growth Retardation by Serial Ultrasonic Cephalometry

Abstract

Abstract. The ultrasonic technique has provided a new and sensitive method for the early detection of retarded intrauterine growth (IUGR).This prospective study investigated the incidence and the intrauterine development of fetuses with retarded growth of the biparietal diameter (BPD). The accordance between retarded BPD growth and IUGR, judged from endpoint observation (reduced fetal size at birth) was established. In a routine screening programme, 1317 pregnant women were examined by ultrasound twice for cephalometry. The BPD determinations were performed in the 19th and 32nd post‐menstrual weeks. Normal increment of the BPD during the interval between the 19th and the 32nd week 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. In the examined 1317 pregnancies, 6.3 % of the fetuses 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 week were in general uniform; that is, head and body dimensions were equally small. This was true also for the placental weight in those pregnancies that were terminated before the 38th week, but thereafter, there was a tendency for the fetus to have outgrown its placenta.The investigation demonstrates that, by only two measurements of the BPD, it is possible to diagnose a large risk group of pregnancies with not only a high proportion of pre‐term deliveries, but also infants with low birth weight. The new approach to fetal growth not only takes birth‐weight into consideration but also, to some extent, the time of onset of the growth retardation.