How does the body typically prepare for labor during the third trimester?

During the third trimester of pregnancy, the body undergoes several physiological changes to prepare for labor, and one key aspect is the relaxation of ligaments. This relaxation is mainly influenced by the hormone relaxin, which is secreted in increased amounts during this period. Relaxin helps to soften and lengthen the connective tissue in the pelvic area, facilitating the expansion needed during childbirth. This process allows the pelvis to be more flexible, making it easier for the fetus to pass through the birth canal during labor.

The other options do not accurately reflect typical preparations for labor. For instance, an increase in blood pressure may occur due to various reasons, but it is not a common or direct preparation mechanism for labor. Similarly, fetal activity often increases or becomes more noticeable in the third trimester, indicating a healthy and active fetus, rather than decreasing. Weight loss is not a standard preparation for labor; instead, many women experience weight gain throughout pregnancy, particularly in the later stages. Thus, ligament relaxation is a crucial and specific adaptation of the body during the third trimester to ensure a successful labor and delivery process.