Cervical function during pregnancy and parturition

During most of pregnancy, the cervix remains unyielding and reasonably rigid. The function of the cervix is to keep the cervical canal closed so that expansion of the uterine cavity may proceed undisturbed. The cervix and cervical mucus also serve as barriers to invading microorganisms.1 At the end of pregnancy, however, the cervix must undergo cervical ripening - defined as increased softening, distensibility, effacement, and early dilation of the cervix by digital examination - to allow successful delivery of the fetus through the cervix and vagina. These two functions of the cervix, i.e. maintenance of intrauterine pregnancy and facilitation of delivery, are diametrically opposed, require tight orche - stration, and must be coordinated with uterine contractions for successful delivery of a term infant.