While the placenta has an effective "barrier" that protects the developing baby from many harmful substances, some infectious organisms may penetrate this protective placental barrier.

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While the placenta does provide a barrier to most harmful substances, some infectious organisms such as certain viruses, bacteria, and parasites may be able to cross the placental barrier and cause harm to the developing baby. This is known as congenital infection or vertical transmission. Examples of infectious agents that can cross the placenta include rubella virus, cytomegalovirus, and toxoplasmosis.

While the Placenta Has an Effective "Barrier" That Protects the Developing