Placental

The American Congress of Obstetricians and Gynecologists, in an opinion from its Committee on Obstetric Practice that was published on the ACOG website, said that instead of quickly clamping off the cord that connects the newborn to its placental sac, doctors should wait an additional 30 to 60 seconds. Those extra seconds for babies born at term are associated with an increase in hemoglobin levels in newborns, the statement said.

We do not know exactly how many placental lineages survived to leave descendants; most estimates are around ten.