In a double-blind randomized controlled trial, Esther Atukunda and colleagues evaluated whether sublingual misoprostol administered to women in labor was non-inferior to intramuscular oxytocin in preventing postpartum hemorrhage and reducing blood loss.
Please see later in the article for the Editors' Summary
Postpartum hemorrhage (PPH) is a leading cause of maternal death in sub-Saharan Africa. Although the World Health Organization recommends use of oxytocin for prevention of PPH, misoprostol use is increasingly common owing to advantages in shelf life and potential for sublingual administration. There is a lack of data about the comparative efficacy of oxytocin and sublingual misoprostol, particularly at the recommended dose of 600 µg, for prevention of PPH during active management of labor.
Methods and Findings
We performed a double-blind, double-dummy randomized controlled non-inferiority trial between 23 September 2012 and 9 September 2013 at Mbarara Regional Referral Hospital in Uganda. We randomized 1,140 women to receive 600 µg of misoprostol sublingually or 10 IU of oxytocin intramuscularly, along with matching placebos for the treatment they did not receive. Our primary outcome of interest was PPH, defined as measured blood loss ≥500 ml within 24 h of delivery. Secondary outcomes included measured blood loss ≥1,000 ml; mean measured blood loss at 1, 2, and 24 h after delivery; death; requirement for blood transfusion; hemoglobin changes; and use of additional uterotonics.
At 24 h postpartum, primary PPH occurred in 163 (28.6%) participants in the misoprostol group and 99 (17.4%) participants in the oxytocin group (relative risk [RR] 1.64, 95% CI 1.32 to 2.05, p<0.001; absolute risk difference 11.2%, 95% CI 6.44 to 16.1). Severe PPH occurred in 20 (3.6%) and 15 (2.7%) participants in the misoprostol and oxytocin groups, respectively (RR 1.33, 95% CI 0.69 to 2.58, p = 0.391; absolute risk difference 0.9%, 95% CI −1.12 to 2.88). Mean measured blood loss was 341.5 ml (standard deviation [SD] 206.2) and 304.2 ml (SD 190.8, p = 0.002) at 2 h and 484.7 ml (SD 213.3) and 432.8 ml (SD 203.5, p<0.001) at 24 h in the misoprostol and oxytocin groups, respectively. There were no significant differences between the two groups in any other secondary outcomes. Women in the misoprostol group more commonly experienced shivering (RR 1.91, 95% CI 1.65 to 2.21, p<0.001) and fevers (RR 5.20, 95% CI 3.15 to 7.21, p = 0.005).
This study was conducted at a regional referral hospital with capacity for emergency surgery and blood transfusion. High-risk women were excluded from participation.
Misoprostol 600 µg is inferior to oxytocin 10 IU for prevention of primary PPH in active management of labor. These data support use of oxytocin in settings where it is available. While not powered to do so, the study found no significant differences in rate of severe PPH, need for blood transfusion, postpartum hemoglobin, change in hemoglobin, or use of additional uterotonics between study groups. Further research should focus on clarifying whether and in which sub-populations use of oxytocin would be preferred over sublingual misoprostol.
Please see later in the article for the Editors' Summary
Every year, worldwide nearly 290,000 women die during pregnancy or labor or during the first six weeks after giving birth (the postpartum period). Almost all of these “maternal” deaths occur in low- or middle-income countries, and most are caused by a handful of preventable or treatable conditions—postpartum hemorrhage (severe bleeding from the uterus [womb] within 24 hours of childbirth), post-delivery infections, unsafe abortion, obstructive (difficult) labor, and blood pressure disorders during pregnancy. The leading cause of maternal deaths worldwide is postpartum hemorrhage, which is responsible for 25%–30% of all maternal deaths. Postpartum hemorrhage can be prevented by giving the mother an intramuscular injection of oxytocin, a hormone that stimulates uterine contractions and limits uterine bleeding, immediately after her child is born.
Why Was This Study Done?
Unfortunately, oxytocin needs to be kept cool, which limits its use in low- and middle-income countries, and, until recently, it was thought that only trained personnel could give intramuscular injections. Consequently, administration of misoprostol, a synthetic prostaglandin that has effects similar to those of oxytocin, has been proposed as an alternative way to prevent postpartum hemorrhage in resource-limited settings. Misoprostol is stable at room temperature, and because it can be given sublingually (beneath the tongue), it acts very quickly. However, the comparative efficacy of sublingual misoprostol and intramuscular oxytocin for the prevention of postpartum hemorrhage has not been established. Here, the researchers undertake a double-blinded, double-dummy randomized controlled non-inferiority trial to compare sublingual misoprostol and intramuscular oxytocin for the prevention of postpartum hemorrhage in Uganda, a country where there are more than 5,500 maternal deaths every year. A randomized controlled trial compares the outcomes of individuals assigned to different interventions through the play of chance. In a double-blinded trial, neither the researchers nor the participants know who is receiving which intervention. In this particular trial, double-blinding is achieved by giving a dummy (placebo) sublingual pill to the women assigned to the oxytocin group and a dummy injection to the women assigned to the misoprostol group, as well as their assigned treatments. A non-inferiority trial investigates whether one treatment is not worse than another treatment.
What Did the Researchers Do and Find?
The researchers measured blood loss over the first 24 hours after delivery in 1,140 women admitted to a regional referral hospital in Uganda. The women were given either sublingual misoprostol or intramuscular oxytocin at the currently recommended doses, along with matching placebos, immediately after the birth of their child. Postpartum hemorrhage (defined as the loss of more than 500 ml of blood within 24 hours of delivery; the trial's primary outcome) occurred in 28.6% and 17.4% of the women in the misoprostol and oxytocin groups, respectively (an absolute risk difference of 11.2%). Severe postpartum hemorrhage (loss of more than 1,000 ml of blood within 24 hours of delivery) occurred in 3.6% and 2.7% of participants in the misoprostol and oxytocin groups, respectively, but this difference was not statistically significant (it could have happened by chance). On average, women given misoprostol had lost slightly more blood by two and 24 hours after delivery than those given oxytocin. There were no significant differences between the groups in terms of death, the need for blood transfusion, or the use of additional drugs to prevent blood loss, but women given misoprostol experienced shivering and fever more often than those given oxytocin.
What Do These Findings Mean?
In their study protocol, the researchers specified that sublingual misoprostol would be deemed non-inferior to intramuscular oxytocin if the absolute risk difference for postpartum hemorrhage between the misoprostol and oxytocin treatment groups was less than 6% (the “non-inferiority” margin). These findings therefore indicate that sublingual misoprostol given at the recommended dose is inferior to intramuscular oxytocin for the prevention of postpartum hemorrhage in women undergoing an uncomplicated birth at a regional referral hospital in Uganda. Although several aspects of this study may affect the accuracy and generalizability of its findings (for example, women at high risk of birth complications were excluded from the study), the researchers conclude that oxytocin should remain the preferred agent for the prevention of postpartum hemorrhage where it is available. However, they note, sublingual misoprostol remains important for the prevention of postpartum hemorrhage where oxytocin is unavailable or its administration is not feasible.
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001752.
The United Nations Children's Fund (UNICEF) provides information on maternal mortality; “Trends in Maternal Mortality: 1990 to 2013” is a recent WHO/UNICEF/UNFPA/World Bank publication that provides up-to-date information on maternal mortality worldwide
The World Health Organization provides information on maternal health (in several languages)
The Postpartum Hemorrhage Prevention and Treatment Website provides a forum for information sharing and learning between organizations and individuals working on the prevention and treatment of postpartum hemorrhage in developing countries; the website includes basic information about postpartum hemorrhage and links to additional resources
“Veil of Tears” contains personal stories (including stories about postpartum hemorrhage) from Afghanistan about loss in childbirth
“Maternal Death: The Avoidable Crisis” is a briefing paper published by Médecins Sans Frontières in 2012
More information about this trial is available