Detection of intrauterine growth retardation: a new use for sonographic placental grading.

Intrauterine growth retardation (IUGR) is a major source of perinatal death and long-term neurobehavioral morbidity, but its diagnosis antenatally remains difficult. Advanced placental maturity (Grade III), as determined on ultrasound examination, has previously been reported to be a marker of term gestation. In this study of 109 pregnancies which resulted in the birth of infants weighing less than or equal to 2,700 gm, the hypothesis that a Grade III placenta, according to Grannum's classification, can differentiate small-for-gestational age (SGA) infants from small non-SGA infants was tested. Of the study patients, 44 had Grade III placentas and 65 had non-Grade III (0, I, II) placentas within 1 week of delivery. The presence of a Grade III placenta was followed by the delivery of a SGA infant 59% of the time, and 62% of the SGA infants could be correctly identified (p less than 0.001). The association of a Grade III placenta and SGA birth was maintained in patients at less than or equal to 34 weeks of gestation--Grade III placenta was significantly related to the delivery of SGA infants with a true positive rate of 62% and a sensitivity of 66% (p less than 0.008). These results were consistent with the concept that for small fetuses documentation of "maturity" can be used to discriminate those with IUGR from those without this problem. Furthermore, placental "maturation," as detected sonographically, appears to be accelerated in association with IUGR, consistent with the anatomic concept of premature placental senescence. Thus, in situations in which the fetus is known to be small, sonographic grading of the placenta may be helpful in detecting IUGR.