A cervical ripening balloon is a medical device used to soften and dilate the cervix during labor induction. It is a small, inflatable device that is inserted into the cervix and gradually filled with saline solution, thus applying pressure to the cervix. This pressure helps to stimulate the natural hormonal processes that soften and dilate the cervix, making it easier for the baby to pass through during labor.　It is a commonly used method to induce labor in women who are overdue or who have medical conditions that make it safer to deliver the baby sooner.