Final answer:
During the second trimester of pregnancy, back pain, leg cramps, heartburn, and swollen feet are common discomforts. As the fetus grows larger, it can put pressure on the mother's back and legs, leading to pain and cramps. The upward pressure of the uterus on the stomach can cause heartburn.
Step-by-step explanation:
During the second trimester of pregnancy, which occurs between weeks 13 to 28, the mother may experience several discomforts. Back pain, leg cramps, heartburn, and swollen feet are common discomforts at 20 weeks gestation. As the fetus grows larger and the uterus expands, it can put pressure on the mother's back and legs, causing pain and cramps. The upward pressure of the uterus on the stomach can lead to heartburn, and the increased weight and fluid retention can cause swollen feet.