Bleeding after birth, also known as postpartum hemorrhage, is the most common reason why mothers die in childbirth worldwide. Although most healthy women can cope well with some bleeding at childbirth, others do not, and this can pose a serious risk to their health and even life.

To reduce excessive bleeding at childbirth, the routine administration of a uterotonic drug called oxytocin, which contracts the uterus, has become standard practice across the world.

In this study, researchers from the Cochrane Pregnancy and Childbirth Group have reviewed the data of the births of 88,000 women who took part in 140 randomized trials, with the aim of identifying which uterotonics (including oxytocin, as well as misoprostol, ergometrine, carbetocin, or combinations of these) are most effective in preventing excessive bleeding after childbirth and have the least side effects.

The Cochrane Review found that ergometrine plus oxytocin; misoprostol plus oxytocin; and carbetocin on its own were more effective drugs for reducing excessive bleeding at childbirth rather than the current standard use of oxytocin on its own.

The team analyzed all the available evidence to compare all of the drugs and calculated a ranking among them, providing robust effectiveness and side effect profiles for each drug. Side effects can include vomiting, high blood pressure, and fever.

University of Birmingham Clinician Scientist Dr. Ioannis Gallos, of the Cochrane Pregnancy and Childbirth Group and review author, said: "Whilst death from postpartum hemorrhage is a rare complication, it is the most common reason why mothers die in childbirth worldwide and happens because a woman's womb has not contracted strongly enough after birth and results in excessive bleeding."

"Currently, to reduce excessive bleeding at childbirth, the standard practice across the world is to administer to women after childbirth a drug called oxytocin—a uterotonic which contracts the uterus and stimulates contractions to help push out the placenta."

"However, there are a number of other uterotonics and combinations of these drugs that can be given that may be more effective."

"By analyzing data from 140 different clinical trials involving over 88,000 women, we have been able to use the evidence more efficiently to compare all of these drugs and calculate a ranking among them, providing robust effectiveness and side effect profiles for each drug."

"Our research has highlighted which drugs may be more effective than oxytocin, and we hope that this could impact existing recommendations and save mothers' lives worldwide."

This Cochrane Review is expected to be updated later this year to incorporate the results of some key ongoing studies, including a large study involving around 30,000 women across 10 different countries comparing the effectiveness of carbetocin vs oxytocin for preventing bleeding in women having a vaginal birth—and a UK-based trial involving more than 6,000 women comparing carbetocin, oxytocin, and ergometrine plus oxytocin combination.