What significant change occurs during the last month of pregnancy?

During the last month of pregnancy, the fetus undergoes significant maturation that prepares it for life outside the womb. This includes the development of respiratory and digestive systems, as well as the ability to regulate body temperature. The fetus starts to practice breathing movements and may even begin to coordinate sucking and swallowing, crucial for feeding after birth. Additionally, the accumulation of body fat and the final maturation of the central nervous system enhance the fetus's ability to adjust to extrauterine life.

The other options, while related to pregnancy, do not specifically highlight the key changes that occur in this final month. All body organs being formed generally occurs during the first and second trimesters, the fetal heartbeat being heard is typically established much earlier in the pregnancy, and while mothers may certainly experience labor pains as they approach delivery, this is more associated with the onset of labor rather than a significant developmental change in the fetus during the last month.