The placenta has no native microbes, scientists say. (Credit: Blue Planet Studio/Shutterstock)

The placenta is a unique organ. The temporary body part forms in the uterus during pregnancy and supplies the developing baby with nutrients and oxygen while also carrying away waste products. The organ is also a common source of pregnancy complications.

Recently scientists have wondered whether microbes might be to blame. Some research has suggested that, like the gut, a host of bacteria coloni