At the time of birth presence of which antibody indicates the infection of foetus (Intrauterine infection)

Options

A. `I_(g)G`
B. `I_(g)O`
C. `I_(g)M`
D. `I_(g)A`

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which antibody's presence at birth indicates that the fetus had an intrauterine infection.

2. **Identifying Antibodies**: There are several types of antibodies, including IgG, IgM, IgA, and IgO. It is important to know their roles and characteristics.

3. **Role of IgG**: IgG is the only antibody that can cross the placenta from the mother to the fetus. Therefore, its presence at birth does not indicate an infection because it is normally found in the fetus.

4. **Role of IgM**: IgM is the first antibody produced in response to an infection. If IgM is present in the newborn, it indicates that the fetus was infected during development since IgM does not cross the placenta.

5. **Role of IgA**: IgA is primarily found in breast milk (colostrum) and is not present in the fetus at birth. Its presence at birth would not indicate intrauterine infection.

6. **Role of IgO**: IgO is not a recognized antibody type in the context of human immunology, making it an incorrect option.

7. **Conclusion**: Since the presence of IgM at birth indicates that the fetus had an intrauterine infection, the correct answer is IgM.

**Final Answer**: The presence of IgM antibody at the time of birth indicates the infection of the fetus (intrauterine infection).

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