Placenta

Placenta


INTRODUCTION


At USG, the placenta may be visible as early as 10 weeks as a thickening of the hyperechoic rim of tissue around the gestational sac.


Fetal placenta—Chorion frondosum—develops from the blastocyst


Maternal placenta—Decidua basalis—develops from maternal uterine tissue


At 12–13 weeks, blood flow is easily demonstrable


By 14–15 weeks—Placenta is well established


Prominent hypoechoic retroplacental area composed of decidua, myometrium, and uterine vessels


Normal-term placenta measures 15–20 centimeters in length and 400–500 grams in weight at term Maximum—4–5 centimeters in thickness


Thin placenta—Small for date fetus


Sign of intrauterine growth retardation (IUGR)


Thick placenta (Placentomegaly)


Homogenous thickening


1.    Diabetes mellitus (Gestational)


2.    Anemia


3.    Hydrops


4.    Infections


5.    Aneuploidy


Heterogenous (With multiple cystic spaces)


1.    Triploidy


2.    Placental hemorrhage


3.    Villitis


4.    Mesenchymal dysplasia


5.    Beckwith–Wiedmann syndrome


Placental Grading—Grannum classification (Figures 21.1 and 21.2)


Grade 0—Homogenous placenta, uniform echogenicity—first and early second trimester


Grade 1—Occasional hypo-/hyperechoic areas—late second trimester


Grade 2—Larger calcifications along the basal plate—early third trimester


Grade 3—Larger and denser calcifications along with compartmentalization of placenta—late third trimester


Image


Figure 21.1 Illustrates grading of placental maturity.


Image


Figure 21.2 Illustrates varying grades of placental maturity in a normal fetus.

Nov 6, 2018 | Posted by in ULTRASONOGRAPHY | Comments Off on Placenta
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