The placenta is the organ that connects the developing baby to its mother during pregnancy. It is where the mother’s and baby’s blood meet to exchange nutrients. At birth it detaches from the inner wall of the womb and is delivered to the outside world along with the newborn baby.

While the placenta may be one of the least understood organs in the human body, it is arguably one of the most important. Scientists have long been interested in how the placenta works, though its importance in human medicine has only recently taken center stage. The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), one of the many institutes at the National Institutes of Health, has recently declared a new initiative called the Human Placenta Project funded to discover ways to safely monitor the placenta at different stages of pregnancy. Why? Because we now know that the placenta is not only associated with several disorders of pregnancy, but more importantly it is also associated with the likelihood that offspring will acquire high blood pressure, heart disease, diabetes and even some cancers as they grow up.

Soon after the human egg is fertilized, it forms an embryo that travels to the womb where it attaches to the womb’s inner lining. As the embryo becomes a fetus, the mature placenta is formed from specialized cells that have two properties: 1) they can invade the lining of the womb like roots on a tree to make a sturdy attachment for the placenta to anchor the baby and 2) they can invade the mother’s arteries in the womb and cause them to enlarge so that blood can more easily flow from the mother into the placenta to provide oxygen and nutrients for the baby. These invading cells are likely to be the regulators of the shape of the placenta and the degree to which it works.

How can we tell if a placenta is healthy? The answer is that in most cases, we can’t –at least with current technology– but we are setting out to change that situation. Scientists are frantically working to find the links between placental health and the long term health of people as they age. Recent studies of the prevalence of chronic diseases from countries where they keep detailed birth and placenta records have shown that small variations in the shape of the placenta are associated with chronic diseases later in life. The next research frontier is to discover how shape is determined and how it predicts diseases during adulthood.

Studying the placenta will bring exciting new discoveries as to why people get diseases as they grow up and reach old age.