The type of immunity passed from mother to fetus is passive immunity.
Understanding Passive Immunity from Mother to Child
Passive immunity is a crucial way for newborn babies to gain protection against diseases immediately after birth. Unlike active immunity, where the body creates its own antibodies, passive immunity involves receiving antibodies directly from another source.
As stated in the reference from the CDC:
Passive immunity is provided when a person is given antibodies to a disease rather than producing them through his or her own immune system. A newborn baby acquires passive immunity from its mother through the placenta.
This means the mother's antibodies, which she has developed through her own past infections or vaccinations, are transferred across the placenta to the developing fetus. These antibodies provide temporary protection to the baby against specific diseases during the first few months of life, while the baby's own immune system is still maturing.
How Does This Transfer Occur?
- Through the Placenta: Antibodies, particularly a type called IgG, are actively transported from the mother's blood into the fetus's bloodstream via the placenta during pregnancy. This transfer is especially significant in the later stages of pregnancy.
This maternally acquired passive immunity offers a vital layer of defense, protecting the infant from common infections during a vulnerable period. The protection is temporary because the baby's body doesn't produce these antibodies itself; they naturally break down over time. The duration and level of protection depend on the specific antibodies transferred and the mother's immunity status.
Key Characteristics of Passive Immunity from Mother:
- Source: Acquired from the mother.
- Mechanism: Transfer of pre-formed antibodies (mainly IgG) across the placenta.
- Onset: Immediate protection is provided.
- Duration: Temporary (lasts for weeks to months).
- Nature: The baby does not develop memory cells for the specific pathogen; protection fades as antibodies degrade.
This passive transfer highlights the incredible connection between mother and child, providing the newborn with a head start in fighting off potential infections.
