Does a picture of the human placenta predict the future?

Article Outline

• Copyright

Is a picture worth a thousand words? In this month’s Placenta two groups underscore how size and shape vary among human placentas and reflect placental function and dysfunction. Pathologists have routinely recorded these features of placental anatomy for decades, if not centuries. Interest in the dimensions of the placenta was rekindled when Barker and colleagues used data derived from midwife recordings of long and short diameters of placentas in a population exposed to the famine induced by war in the 1940’s. Their conclusion was that small placentas yielded small babies predisposed to cardiovascular complications in adult life. This finding, along with many other data, led to the explosion of publications describing the developmental origins of human adult disease (DOHAD).

More recently, attention has also been directed to the role of the placenta in determining long term health aspects of the mother and the premise has been posed that placental dysfunction during pregnancy unveils underlying maternal risks for cardiovascular and other disease processes, or lowers the threshold for such diseases in the decades to come in the woman’s life. Dubbed with the mnemonic CHAMPS, or cardiovascular health and maternal placental syndromes, this area of research is also blossoming, as investigators relate the mass of placenta and how the mother reacts to abnormal structure and function of this pivotal organ to yield lifelong changes in pathophysiology.

What is the shape of the normal human placenta? Most textbook diagrams of the human placenta draw relative circles as the delimiting characteristic of the perimeter of this fetal organ. Accompanying this image commonly is a relatively uniform distribution of fetal vessels over the chorionic plate as they emanate from a centrally inserted umbilical cord. The authors of two papers published in tandem in this issue of Placenta have differing opinions on the normal shape of the human placenta. Salafia and colleagues conclude that the mean placental chorionic shape at term is round and that increased deviation from this shape associates with lower placental efficiency, and the presence of either maternal or fetoplacental vascular pathology. Lees and colleagues study a large unselected population of human placentas at delivery and conclude that normal placental shapes are elliptical with cord insertions most commonly not centrally located. Both sets of authors use mathematical formulas to derive quantitative evaluations of the gross structure of the placenta. They come to different conclusions from their data, and in the peer review process, the senior author of each paper kindly reviewed the other’s work. They are both to be complimented for application of quantitative analyses to what have all too often previously been subjective assessments of the gross appearance of the human placenta. They also agreed to disagree.

Who cares what the size and shape of the placenta is? The DOHAD and CHAMPS data suggest the structure and function of the placenta is important and may be a readily available window to the future risks for both mother and baby, for such complications as cardiovascular disease and diabetes, among others. Indeed, as proposed by Salafia, a simple picture of the chorionic surface of the placenta for length, width, and breadth measurements of the placenta may provide key information to enhance our predictive value for adult disorders. If this is the case, a picture is worth a thousand words. You, as the audience reading the literature will be the entity to determine what is truth, as you read the approaches and review the data supplied by Salafia and by Lees.