labor prostaglandins

Labor prostaglandins are local chemical signals that help get the body ready for birth and then keep contractions going, working close to where they are made rather than traveling far through the blood. If oxytocin is the long-distance call to contract, prostaglandins are the neighborhood messengers preparing the ground.

Prostaglandins are lipid signaling molecules (eicosanoids), made in the uterus, cervix and fetal membranes from fatty acids. As pregnancy nears term, their production rises. Two effects are central: they soften and thin the cervix, a process called cervical ripening, and they stimulate the uterine muscle to contract, working alongside and amplifying the action of oxytocin.

Because of these actions, synthetic prostaglandins are used clinically to ripen the cervix and induce labor. Conversely, drugs that block prostaglandin production (such as some anti-inflammatory medicines) can suppress contractions, which is why they are sometimes used cautiously to delay preterm labor.

A caveat: prostaglandins act broadly throughout the body, so drugs affecting them have effects far beyond the uterus, including on the stomach, kidneys and the fetal circulation. This is why prostaglandin-blocking tocolytics are used only carefully and for limited periods.