Sonographically, hematomas evolve with time and appear hyperechoic to isoechoic in the irst week after hemorrhage, hypoechoic at 1 to 2 weeks, and inally, anechoic after 2 weeks. Most subchorionic hematomas visible sonographically are fairly small and of no clinical consequence. However, extensive retroplacental, marginal, and subchorial collections have been associated with higher rates of miscarriage, stillbirth, placental abruption, and preterm delivery (Ball, 1996; Fung, 2010; vladu, 2006; Tuuli, 2011). In essence, placental abruption is a large, clinically signiicant retroplacental hematoma.
Placental lesions that arise from fetal circulatory disturbances are also depicted in Figure 6-3. Deoxygenated fetal blood lows from the two umbilical arteries into arteries within the chorionic plate that divide and send branches out across the placental surface. hese eventually supply individual stem villi, and their thrombosis will obstruct fetal blood low. Distal to the obstruction, afected portions of the villus become nonfunctional. Thrombi in limited numbers are normally found in mature placentas. If many villi are afected, which can be seen with preeclampsia, the fetus may sufer growth restriction, stillbirth, or nonreassuring fetal heart rate patterns (Chisholm, 2015; Lepais, 2014; Saleemuddin, 2010).
here is a spectrum of villous capillary lesions. Chorangiosis describes an increased number of capillaries within terminal villi. Its deinition requires :::10 capillaries to be present in :::10 villi in :::10 ields viewed through a lOx microscope lens (Altshuler, 1984). Clinically, long-standing hypoperfusion or hypoxia is thought to be causative (Stanek, 2016). It is often associated with maternal diabetes mellitus (Ogino, 2000). Chorangiomatosis describes increased capillary number in stem villi, but terminal villi are spared. his inding has been linked with fetal-growth restriction and anomalies (Bagby, 2011). Despite these associations, the clinical signiicance of both vascular conditions remains unclear. Chorioangiomas are described subsequently.
As indicated earlier, these hematomas lie between the chorionic plate and amnion. They most often are acute events during third-stage labor when cord traction ruptures a vessel near the cord insertion.
Large chronic antepartum lesions may cause fetomaternal hemorrhage or fetal-growth restriction (Deans, 1998). They also may be confused with other placental masses such as chorio angioma. In most cases, Doppler interrogation will show absent internal blood low within a hematoma and permit differentiation (Sepulveda, 2000).
Calcium salts can be deposited throughout the placenta but are most common on the basal plate. Calciication accrues with advancing gestation, and greater degrees are associated (Bedir Findik, 2015; Klesges, 1998; McKenna, 2005). These hyperechoic deposits can easily be seen sonographically, and a grading scale from 0 to 3 relects increasing calciication with increasing numerical grade (Grannum, 1979). Following this scheme, a grade 0 placenta is homogeneous, lacks calciication, and displays a smooth, lat chorionic plate. A grade 1 placenta lations. Grade 2 shows echogenic stippling at the basal plate.
Large, echogenic comma shapes originate from an indented chorionic plate, bur their curve falls short of the basal plate.
Last, a grade 3 placenta has echogenic indentations extending from the chorionic plate to the basal plate, which create discrete components that resemble cotyledons. Basal plate densities also increase.