Which hormone increases the flexibility of the pelvis during pregnancy?

Relaxin is the hormone responsible for increasing the flexibility of the pelvis during pregnancy. It is produced by the placenta and the ovaries and plays a critical role in preparing a woman's body for childbirth. The increased levels of relaxin lead to the relaxation of the ligaments and softening of the cervix, facilitating the expansion of the pelvis and aiding in labor and delivery. This flexibility helps accommodate the growing fetus and allows for the necessary adjustments during the birthing process.

Estrogen and progesterone are important hormones during pregnancy but primarily focus on the development of the pregnancy and not specifically on the flexibility of the pelvis. Estrogen is involved in regulating the growth of uterine tissue and other reproductive functions, while progesterone helps maintain the uterine lining and supports pregnancy. Oxytocin is essential for initiating labor and promoting uterine contractions but does not play a direct role in pelvic flexibility.