What medication is used to prevent postpartum hemorrhage? A comprehensive guide

October 12, 2025 •

4 min read

Postpartum hemorrhage (PPH), defined as blood loss of 500 mL or more within 24 hours of delivery, is a leading cause of maternal morbidity and mortality worldwide. The most effective strategy to prevent this life-threatening complication is Active Management of the Third Stage of Labor, which centers on the administration of a uterotonic medication, with oxytocin being the first-line choice. This article details what medication is used to prevent postpartum hemorrhage and how these critical interventions function.

Quick Summary

Postpartum hemorrhage prevention relies on uterotonic drugs like oxytocin, administered immediately after delivery to trigger uterine contractions. Alternative medications, including misoprostol and carbetocin, are used when oxytocin is unavailable, as part of active management of labor. Timely medication is key to minimizing blood loss and preventing severe complications.

Key Points

Oxytocin is the first-line choice: It is the standard uterotonic medication used universally to prevent PPH by stimulating uterine contractions.
Active management is key: The prophylactic administration of a uterotonic is the most important component of Active Management of the Third Stage of Labor (AMTSL) for all births.
Alternatives are available: Misoprostol is a viable alternative, especially in low-resource settings, due to its heat stability and ease of administration, though it carries more side effects than oxytocin.
Consider other uterotonics with caution: Medications like methylergonovine are effective but carry significant contraindications, such as hypertension.
Adjunctive therapy for treatment, not routine prevention: Tranexamic acid is an antifibrinolytic used to treat established PPH, but current guidelines do not recommend it for routine prophylactic use, although research is ongoing for high-risk individuals.
Higher risk requires more planning: Women with pre-existing risk factors require heightened vigilance, and their delivery plans should include protocols for managing potential hemorrhage.

The Foundation of Prevention: Uterotonics and Active Management

Prevention is the most critical aspect of managing postpartum hemorrhage (PPH). The World Health Organization (WHO) and other major health organizations recommend the routine practice of Active Management of the Third Stage of Labor (AMTSL) for all births. The most important component of AMTSL is the prophylactic administration of a uterotonic drug, which causes the uterus to contract and constrict the blood vessels that supplied the placenta. By doing so, uterotonics help the uterus achieve hemostasis after placental delivery, significantly reducing the risk of PPH.

First-Line Medication: Oxytocin

Oxytocin is the standard of care and the first-line medication recommended globally for preventing postpartum hemorrhage. It is a naturally occurring hormone that, when administered synthetically, stimulates strong, rhythmic uterine contractions.

Mechanism of Action: Oxytocin acts on receptors in the myometrium (the muscle layer of the uterus) to increase the frequency and force of uterine contractions. These contractions help to clamp down on the open blood vessels in the uterine wall where the placenta was attached, stopping the bleeding.
Administration: Oxytocin is typically given via an intramuscular injection (IM) of 10 international units (IU) or as a slow intravenous (IV) bolus or infusion. It is administered with or immediately after the delivery of the baby. For vaginal deliveries, intravenous administration has been shown to be more effective than intramuscular for preventing PPH and reduces the need for blood transfusion.
Advantages: Oxytocin is fast-acting, highly effective, and generally has a favorable side-effect profile, with few adverse effects when administered correctly.

Alternative and Adjunctive Medications

While oxytocin is the first choice, other medications are used, especially in situations where oxytocin is not available, is contraindicated, or fails to stop bleeding.

Misoprostol: This prostaglandin E1 analogue can be used for PPH prevention, particularly in low-resource settings where oxytocin may not be readily available due to its need for refrigeration. It is a heat-stable tablet that can be administered orally, sublingually, or rectally. While effective, it is associated with more side effects than oxytocin, including shivering and fever.
Carbetocin: A newer, long-acting synthetic analogue of oxytocin, carbetocin produces sustained uterine contractions and is heat-stable. It is an effective option, with a side-effect profile similar to oxytocin.
Ergot Alkaloids (e.g., Methylergonovine): This class of drugs causes powerful and prolonged uterine contractions. However, it also causes widespread vasoconstriction and is therefore contraindicated in women with hypertensive disorders, including pre-eclampsia.
Tranexamic Acid (TXA): Although primarily a treatment for existing PPH, recent studies have explored its prophylactic use in high-risk women, such as those undergoing cesarean delivery or with moderate-to-severe anemia. TXA is an antifibrinolytic that helps stabilize blood clots, and it is most effective when given within three hours of childbirth. However, it is not a uterotonic and does not replace standard prophylactic measures like oxytocin.

Comparison of Common PPH Prevention Medications


Medication	Class	Mechanism of Action	Administration	Common Side Effects	Contraindications & Cautions
Oxytocin	Synthetic hormone, uterotonic	Stimulates uterine muscle contractions to constrict blood vessels.	10 IU IM or 5–10 IU IV bolus.	Nausea, vomiting, hypotension with rapid IV infusion.	Careful monitoring with prolonged use to avoid water intoxication.
Misoprostol	Prostaglandin E1 analogue, uterotonic	Causes uterine contractions and increased uterine tone.	600 mcg orally or 800-1000 mcg rectally/sublingually.	Shivering, fever, diarrhea, nausea, vomiting.	Avoid with concurrent anticoagulant therapy and caution in patients with cardiovascular disease.
Carbetocin	Long-acting oxytocin analogue, uterotonic	Causes sustained uterine contractions.	100 µg IM or IV.	Side-effect profile similar to oxytocin.	Caution required in specific cardiovascular conditions.
Methylergonovine	Ergot alkaloid, uterotonic	Induces tetanic uterine contractions and vasoconstriction.	0.2 mg IM.	Increased blood pressure, nausea, vomiting.	Absolute contraindication in hypertension and pre-eclampsia.

Considerations for High-Risk Patients

Certain maternal conditions increase the risk of PPH, necessitating careful planning and preparedness.

Risk Factors: Risk factors include a history of PPH, multiple pregnancies, pre-eclampsia, uterine fibroids, and previous cesarean delivery.
Preparation: For high-risk women, delivery may be planned at a facility with immediate access to a blood bank and surgical services.
Anemia Management: Addressing pre-existing maternal anemia before delivery can improve a woman's tolerance for blood loss.

Conclusion: A Coordinated Approach to PPH Prevention

Preventing postpartum hemorrhage is a cornerstone of maternal healthcare, and pharmacologic interventions are central to this effort. The foundation of prevention is the routine administration of oxytocin as part of Active Management of the Third Stage of Labor for all births. For specific circumstances, such as in low-resource settings or if oxytocin is unavailable, other uterotonics like misoprostol provide valuable alternatives. For the highest-risk patients, a layered approach involving careful antenatal assessment, optimized delivery plans, and adjunctive treatments like tranexamic acid during treatment can further reduce the likelihood of a life-threatening hemorrhage. Ultimately, timely, evidence-based pharmacologic interventions, combined with careful monitoring and readiness for complications, are vital for improving maternal outcomes globally.

World Health Organization Guidelines on Postpartum Hemorrhage

Frequently Asked Questions

Oxytocin is the preferred medication because it is highly effective at inducing uterine contractions, acts quickly, and has a favorable side-effect profile compared to alternative uterotonics.

Yes, misoprostol is a suitable alternative for PPH prevention, especially in settings where oxytocin cannot be stored or administered effectively. However, it is generally considered less effective than oxytocin and has more side effects, such as shivering and fever.

AMTSL is a package of interventions recommended for all deliveries to prevent PPH. Its key components include administering a prophylactic uterotonic drug (preferably oxytocin), controlled cord traction, and uterine massage after placental delivery.

Tranexamic acid is primarily a treatment for existing postpartum hemorrhage to reduce bleeding, not a routine prophylactic medication. It works by stabilizing blood clots, and current evidence for its use in prevention is mostly limited to high-risk circumstances.

Side effects vary by medication. Oxytocin can cause mild nausea or vomiting. Misoprostol commonly causes shivering and fever. Other uterotonics, like ergot alkaloids, can increase blood pressure.

Risk factors include a history of PPH, prolonged labor, multiple births, placental problems (abruption or previa), and pre-eclampsia. However, PPH can occur unexpectedly in women with no known risk factors.

For prevention, a uterotonic drug like oxytocin is administered with or immediately after the delivery of the baby. For treatment of active bleeding, medication should be administered as soon as possible after diagnosis.