Postpartum Hemorrhage

Postpartum hemorrhage (PPH) is excessive bleeding following childbirth and is a leading direct cause of maternal mortality worldwide. The most common cause is uterine atony, the failure of the uterus to contract adequately after delivery of the placenta.

Definition

Postpartum hemorrhage is excessive bleeding from the genital tract after birth; it is conventionally classified as primary (early) when occurring within the first 24 hours after delivery and secondary (late) when occurring after 24 hours up to several weeks postpartum.

Scope

This topic covers the definition of postpartum hemorrhage, its principal causes (commonly organized as the 'four Ts'), the distinction between early (primary) and late (secondary) hemorrhage, and its epidemiologic burden. It is a reference and educational entry and contains no dosing or individualized management instructions.

Core questions

• How is postpartum hemorrhage defined and classified?
• What are the principal causes of postpartum hemorrhage?
• Why is uterine atony the leading cause?
• What is the global burden of postpartum hemorrhage?

Key concepts

• Uterine atony
• The four Ts (tone, trauma, tissue, thrombin)
• Primary (early) versus secondary (late) hemorrhage
• Retained placental tissue
• Genital tract trauma
• Coagulopathy
• Estimated blood loss

Mechanisms

Effective control of bleeding after birth depends on the uterus contracting to compress the spiral arteries at the placental site. The principal causes are commonly grouped as the 'four Ts': tone (uterine atony, the most frequent), trauma (lacerations or rupture of the genital tract), tissue (retained placenta or membranes preventing uterine contraction), and thrombin (coagulation disorders). Atony predominates because adequate myometrial contraction is the primary hemostatic mechanism after placental separation.

Clinical relevance

Postpartum hemorrhage is an obstetric emergency and a major contributor to maternal death and severe morbidity, especially where access to timely care is limited. Prevention is closely tied to management of the third stage of labor. This entry describes the condition for orientation and does not provide diagnostic thresholds, dosing, or treatment instructions for any individual.

Epidemiology

Postpartum hemorrhage complicates a substantial proportion of deliveries and is among the leading direct causes of maternal mortality globally, with the heaviest burden in low-resource settings. Uterine atony accounts for the majority of cases.

Evidence & guidelines

Systematic reviews characterize the epidemiology and causes of postpartum hemorrhage, and major obstetric guidance addresses its prevention and recognition, including the role of active management of the third stage of labor in reducing severe blood loss.

History

Hemorrhage has long been recognized as a principal cause of maternal death. Twentieth- and twenty-first-century work clarified the relative frequency of its causes and established the prevention paradigm centered on active management of the third stage and prompt recognition.

Debates

How should postpartum hemorrhage be defined and measured?

Definitions based on estimated blood loss thresholds are limited by inaccurate visual estimation, and there is ongoing discussion about whether volume-based, sign-based, or combined definitions best identify clinically significant hemorrhage.

Key figures

• Guillermo Carroli
• Cecily Begley

Seminal works

• carroli-2008
• main-2017

Frequently asked questions

What is the most common cause of postpartum hemorrhage?

Uterine atony, the failure of the uterus to contract adequately after delivery of the placenta, is the most common cause.

What do the 'four Ts' refer to?

They are a mnemonic for the main causes of postpartum hemorrhage: tone (uterine atony), trauma (genital tract injury), tissue (retained placenta), and thrombin (coagulation problems).