Which hormone, along with progesterone, prepares the joints of the pelvis for childbirth?

The hormone that plays a crucial role alongside progesterone in preparing the joints of the pelvis for childbirth is relaxin. During pregnancy, relaxin is produced in significant amounts to allow for the softening of connective tissues, particularly around the pelvic joints. This softening is essential as it enables the pelvis to expand and accommodate the baby's passage during delivery.

This hormone not only facilitates changes in the pelvic area but also affects ligaments throughout the body, contributing to increased flexibility and minimizing the risk of injury during childbirth. The action of relaxin is vital for a safe delivery, making it a key player in the physiological changes that occur during pregnancy. Other hormones like estrogen, oxytocin, and prolactin play significant roles in reproductive processes and lactation, but they do not specifically target the joint preparation necessary for the birthing process in the same way relaxin does.