Which hormone is most directly associated with cervical ripening and labor readiness by acting on the cervix?

• A. Estrogen
• B. Corticotropin-releasing hormone (CRH)
• C. Progesterone
• D. Prostaglandins

Answer: (D)

Prostaglandins directly influence cervical ripening by acting on the cervix to remodel the cervical tissue. They promote softening, dilation, and effacement by increasing collagen breakdown and changing the extracellular matrix, which makes the cervix more pliable and receptive to contractions. This local action is what signals labor readiness, and prostaglandins (such as those used in clinical induction) are specifically employed to ripen the cervix. Other hormones do influence labor in important ways—for example, estrogen can enhance prostaglandin production and receptor expression, and progesterone maintains pregnancy, with ripening occurring as its influence wanes—but the most direct, primary driver of cervical change is the action of prostaglandins on the cervical tissue.