Grannum et al described ultrasonographic changes in the placenta seen during fetal maturation. The authors are from Yale University.



(1) chorionic plate

(2) placental substance

(3) basal layer



Chorionic Plate

Placental Substance

Basal Layer

Grade 0

straight and well defined


no densities

Grade I

subtle undulations

few scattered echogenic areas

no densities

Grade II

indentations extending into placenta but not to basal layer

linear echogenic densities ("comma like")

linear arrangement of small echogenic areas ("basal stippling")

Grade III

indentations communicating with basal layer

circular densities with echo-spared areas in center; large, irregular densities may cast acoustic shadows

large and somewhat confluent basal echogenic areas; may cause acoustic shadows

after Table I, page 918


More than 1 grade may seen when different sections are examined. The grade assigned is based on the most mature region.




Grade 0

seen during first and second trimester, usually appears after 12 weeks gestation

Grade I

appears as early as 30-32 weeks and may persist to term

Grade II


Grade III

mature placenta seen during third trimester


Correlations with abnormal development:

(1) Premature aging (higher than expected grade) may be associated with intra-uterine growth retardation or preeclampsia.

(2) Persistence of Grade 0 into the third trimester may be associated with cardiovascular or renal abnormalities.


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