Define the second trimester.

• A. Weeks 28-40 of pregnancy
• B. Weeks 1-12 of pregnancy
• C. Fluid-filled membrane surrounding fetus
• D. Weeks 13-27 of pregnancy

Answer: (D)

The second trimester spans from about week 13 to week 27 of pregnancy. This mid-stage sits after the first trimester (weeks 1–12) and before the third (weeks 28–40). By this time most major organs are formed and continue to mature, the fetus grows quickly, and fetal movements are often felt by the mother. Ultrasound findings become clearer as fetal anatomy develops, and many find that morning sickness eases during this period. The other options describe a different time frame or a structure around the fetus (the amniotic sac), not a period of gestation. So, weeks 13–27 best define the second trimester.