Define the third trimester.

• A. Weeks 28-40 of pregnancy
• B. Weeks 1-12 of pregnancy
• C. Connects fetus to placenta
• D. Fluid cushioning fetus

Answer: (A)

The third trimester is the final stage of pregnancy, starting at about week 28 and lasting until birth (around week 40). It’s when the fetus undergoes rapid growth and vital organs—especially the lungs—continue to mature so the baby can survive outside the womb. Weight increases, fat layers build up, and brain development progresses during this period, all preparing for life outside maternal support.

Other statements describe different ideas: the early weeks correspond to the first trimester, the component that connects the fetus to the placenta is the umbilical cord, and the surrounding fluid that cushions the fetus is amniotic fluid.