The term “Jeanty” on an ultrasound report refers to a system used to assess the maturity of the placenta, the temporary organ that provides oxygen and nutrients to the developing fetus. The Jeanty classification is a common method used by sonographers and clinicians to describe how much the placenta has aged based on its visual characteristics on the ultrasound scan.
The placenta acts as the life support system for the fetus, filtering waste and facilitating gas exchange. Like all organs, the placenta changes throughout pregnancy, and the classification system monitors this normal aging process. The assigned grade provides information about the placenta’s current state, which is always considered alongside many other factors of your pregnancy.
Defining the Jeanty Classification
The “Jeanty classification” is often used interchangeably with the Grannum classification, which is the standardized method it describes. This system provides an objective way to categorize the physical changes a placenta undergoes from early pregnancy until full term. The classification assigns a grade from 0 to 3 based on the appearance of the chorionic plate, the placental substance, and the basal layer.
Placental maturation involves the accumulation of calcium deposits, known as calcification, which alters the organ’s appearance on an ultrasound. Monitoring maturity is important because the placenta’s ability to function can gradually decrease as it ages. This grading system allows healthcare providers to track the normal progression of these visual changes throughout the trimesters.
Understanding the Placental Grading Scale
The grading scale uses four distinct levels, from Grade 0 (least mature) to Grade 3 (most mature), each corresponding to specific sonographic features. These visual characteristics reflect the underlying changes in the placental structure as the pregnancy advances. The progression through these grades is a natural part of a healthy, full-term pregnancy.
A Grade 0 placenta is typically seen before 18 weeks, during the first and early second trimesters. On the scan, the chorionic plate—the side facing the fetus—appears as a smooth, well-defined line without any visible indentations. The internal placental tissue is homogeneous, meaning it has a uniform appearance without bright spots that would indicate calcification.
The next step is Grade 1, commonly observed between 18 and 29 weeks of gestation. At this stage, the smooth chorionic plate may begin to show subtle, fine undulations or indentations. Small, scattered calcifications may appear within the placental substance itself, presenting as tiny bright spots randomly dispersed in the tissue.
Moving to Grade 2, which is often found from about 30 to 38 weeks, the visual changes become more pronounced. The indentations along the chorionic plate deepen, reaching into the placental tissue but not extending all the way to the basal layer. Calcifications become larger and may start to accumulate along the basal plate, the area where the placenta attaches to the uterine wall.
The final and most mature stage is Grade 3, which is typically seen at or near full term, generally after 39 weeks. This grade is characterized by indentations that now reach completely through the placental substance to the basal layer, creating a segmented or lobulated appearance often described as cotyledons. Significant and often irregular calcifications are present in both the basal layer and the placental substance, indicating a fully mature organ.
Clinical Significance of Placental Grading
The progression of the placental grade is generally a function of gestational age, meaning the grade usually increases as the pregnancy gets closer to term. Finding a Grade 3 placenta at 39 weeks is a normal and expected sign of maturity. Clinical interest arises when the grade is significantly mismatched with the gestational age, which is termed premature placental calcification.
Finding a Grade 3 placenta before 34 to 37 weeks is considered a sign of accelerated or premature aging. This finding may prompt additional monitoring, such as checking for fetal growth restriction or poor blood flow. A prematurely aged placenta might be less efficient at nutrient and oxygen transfer. Accelerated maturation has been associated with conditions like smoking, chronic hypertension, or certain autoimmune diseases.
Conversely, an unusually low grade, such as a Grade 0 or 1 late in the third trimester, is less common but usually not a cause for alarm on its own. While it can sometimes be associated with conditions like gestational diabetes, it does not carry the same level of concern as premature aging. In the absence of other concerning findings, delayed maturation is typically considered benign. The Jeanty grade is only one piece of information, and its significance is always evaluated alongside the fetus’s overall growth, amniotic fluid levels, and blood flow measurements.