Medical uses Cervical ripening In the setting of labor and delivery, cervical ripening (also known as cervical effacement) is a natural process that occurs before labor, in which the cervix becomes softer, thinner, and dilated, enabling the fetus to pass through the cervix. A ripe cervix is favorable prior to induction of labor, which is a common obstetric practice, and increases the chances for a successful induction. Pharmacological methods are sometimes required to induce cervical ripening that does not occur naturally. The natural ripening of the cervix is mediated by prostaglandins, thus a common pharmacological method is to use external prostaglandins such as PGE2, or dinoprostone. Results of a systematic review and meta-analysis of the literature found that outpatient cervical ripening with dinoprostone or single-balloon catheters did not increase the risk of cesarean deliveries. PGE2 achieves cervical ripening and softening by stimulating uterine contractions as well as directly acting on the collagenase present in the cervix to soften it. There are currently two formulations of PGE2 analog available for use in cervical ripening: Prepidil, a vaginal gel, and Cervidil, a vaginal insert. PGE2 is similar to oxytocin in terms of successful labor induction and the time from induction to delivery. Termination of intrauterine pregnancy Prostaglandin E2 (PGE2) is a common pharmacological method of termination of pregnancy, particularly in the second trimester or for missed abortion, which is a miscarriage in which the fetus did not evacuate the uterus. However, PGE2 is not feticidal, and only induces abortion by stimulating uterine contractions. It is recommended that 20 mg of dinoprostone vaginal suppository be administered every three to five hours to evacuate the uterus. The abortion should occur within 24 hours after the beginning of administration of dinoprostone; if it does not, dinoprostone should no longer be given and other interventions would be required, such as dilation and curettage. Side effects A common side effect of prostaglandin E2 is its effect on gastrointestinal smooth muscle resulting in nausea, vomiting and diarrhea. Other side effects include headache, shivering, and chills. The suppository form of prostaglandin E2 is associated with increased severity of these symptoms. Fever is also a common side effect with use of prostaglandin E2. Administration of prostaglandin E2 should be stopped if a person experiences side effects such as fever. The insert and gel forms have been shown to have minimal gastrointestinal effects, but are more associated with increase stimulation of