Final answer:
Weightlifting is the activity among the choices that is considered less safe during pregnancy. While running, swimming, and yoga are typically acceptable and can be adapted as a pregnancy progresses, weightlifting may need to be significantly modified or avoided due to the physiological changes and risk of injury. So the correct answer is option number 3.
Step-by-step explanation:
During pregnancy, maintaining physical fitness is important for both the mother's and the baby's well-being. However, not all activities are considered safe. The activities listed that are acceptable for most pregnant women include running, swimming, and yoga. These exercises are generally low impact and can be modified to accommodate the changes in a pregnant woman’s body. On the other hand, weightlifting can be contentious, particularly if it involves heavy weights or significant strain on the body. It's not that weightlifting is entirely off-limits, but it should be approached with caution and potentially modified, as the body undergoes significant changes such as increased laxity in joints and shifts in the center of gravity, which can affect balance and increase the risk of injury.
Aside from exercise considerations, it's also important to note other changes during pregnancy, such as the roles of estrogen, progesterone, and hCG in maintaining pregnancy, contributors to weight gain such as the growing fetus and increased blood volume, and the major changes in the maternal digestive, circulatory, and integumentary systems. Understanding these changes helps in determining what physical exercises are appropriate.
Ultimately, it is crucial that any physical exercise regimen during pregnancy is cleared by a healthcare provider who understands the individual's medical history and the specifics of their pregnancy. In summary the correct answer is option number 3.