Question

Which of the following cannot pass through placenta?

• A. Alcohol
• B. Fatty acids
• C. Iron
• D. Maternal antibodies

Hint:

While most nutrients pass through the placenta, maternal antibodies are not directly transferred to the fetus.

Answer 1

The Correct Option is D

Step 1: Understand the placenta.
The placenta acts as a selective barrier that allows the exchange of gases, nutrients, and waste products between the mother and fetus, but it also restricts certain substances.
Step 2: Review the options.
- Alcohol can pass through the placenta and affect the fetus, leading to fetal alcohol syndrome.
- Fatty acids can pass through the placenta to provide energy to the fetus.
- Iron is transported across the placenta to the fetus for its development.
- Maternal antibodies cannot pass through the placenta, as they are typically too large to be transferred.
Step 3: Conclude.
Maternal antibodies do not pass through the placenta, making option (D) the correct answer.
Final Answer: \[ \boxed{\text{Maternal antibodies}} \]