Power and Schulkin reveal the amazing evolution of the human
placenta--and in so doing show how each of our lives began.
As the active interface of the most biologically intimate connection
between two living organisms, a mother and her fetus, the placenta is
crucial to human evolution and survival. Michael L. Power and Jay
Schulkin explore the more than 100 million years of evolution that led
to the human placenta and, in so doing, they help unravel the mysteries
of human life's first moments.
Starting with some of the earliest events that have influenced the path
of placental evolution in mammals and progressing to the specifics of
the human placenta, this book examines modern gestation within an
evolutionary framework. Human beings are a successful species and our
numbers have increased dramatically since our earliest days on Earth.
However, human fetal development is fraught with poor outcomes for both
the mother and fetus that appear to be, if not unique, far more common
in humans than in other mammals. High rates of early pregnancy loss,
nausea and vomiting during pregnancy, preeclampsia and related maternal
hypertension, and preterm birth are rare or absent in other mammals yet
not unusual in humans.
Power and Schulkin explain why this apparent contradiction exists and
address such topics as how the placenta regulates and coordinates the
metabolism, growth, and development of both mother and fetus, the
placenta's role in protecting a fetus from the mother's immune system,
and placental diseases. In the process, they reveal the vital importance
of this organ--which is composed mostly of fetal cells--for us as
individuals and as a species.
