What role does the hormone relaxin play during pregnancy?

Relaxin plays a vital role during pregnancy by promoting the physical adaptations necessary for childbirth, particularly in helping to widen the pelvis. This hormone is produced by the placenta and the corpus luteum and works by relaxing the ligaments and joints in the pelvis, enabling them to become more flexible. This increased flexibility accommodates the growing fetus and facilitates a smoother delivery process.

While other options may seem relevant to various aspects of pregnancy, they do not accurately represent the primary function of relaxin. For instance, relaxin does not have a role in strengthening uterine contractions or accelerating fetal growth; these processes are influenced by other hormones such as oxytocin and human growth hormone. Additionally, relaxin is not involved in preventing morning sickness; the causes of morning sickness are complex and not directly related to this hormone. Thus, the correct choice highlights the essential role of relaxin in preparing the body for childbirth through pelvic widening.