What is the most common cause of PPH?

NORCET 2 - 2021 (shift-1)

Obstetrics & Gynaecology

Easy

Appeared in: NORCET 2 - 2021 (shift-1)

Explanation

Atonicity of the uterus, or uterine atony, is the failure of the uterine myometrium to contract adequately after childbirth.
This lack of contraction leaves the spiral arteries at the former placental implantation site open and bleeding profusely.
It is the single most common cause of postpartum hemorrhage (PPH), responsible for approximately 80% of all cases.

Option B: While trauma to the genital tract (lacerations, hematomas) is a significant cause of PPH, it is the second most common, accounting for about 20% of cases, not the most common.
Option C: Oxytocics (uterotonics) are medications, such as oxytocin and methylergometrine, that are administered to stimulate uterine contractions to prevent or treat PPH. They are a treatment, not a cause.
Option D: Precipitous labor (a very rapid labor) is a risk factor that increases the likelihood of developing uterine atony or genital tract trauma. It is not the direct underlying cause itself.

Visual 1: Diagram: The '4 Ts' of Postpartum Hemorrhage (Tone, Trauma, Tissue, Thrombin), illustrating their relative contributions with a pie chart.
Visual 2: Illustration: A comparison of a well-contracted (firm) postpartum uterus versus an atonic (boggy) uterus, showing the effect on blood vessels.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Causes of Postpartum Hemorrhage (PPH) as background academic context rather than a clinical decision trigger.
Immediate assessment of uterine tone by palpating the fundus is a critical nursing action after every delivery. A firm, 'grapefruit-like' fundus is reassuring, while a soft or 'boggy' fundus indicates atony and requires immediate intervention.
The '4 Ts' mnemonic provides a systematic and rapid framework for nurses and providers to diagnose and manage PPH, ensuring they address the most likely cause first.
What if? If a patient's uterus is firm and contracted but she continues to bleed bright red blood, the nurse's priority shifts from 'Tone' to 'Trauma'. The next step is to anticipate and assist with a thorough inspection of the cervix, vagina, and perineum for lacerations that require repair.

How to Approach the Question

First, identify the core of the question by looking at the keywords: 'most common cause' and 'PPH' (Postpartum Hemorrhage).
Recall the primary etiologies of PPH. The '4 Ts' mnemonic (Tone, Trauma, Tissue, Thrombin) is a standard framework for this.
Access your knowledge about the relative frequency of each of the '4 Ts'. Remember that uterine atony ('Tone') is responsible for the vast majority of cases.
Evaluate the given options in the context of the '4 Ts'. 'Atonicity of uterus' directly corresponds to the 'Tone' category.
Critically analyze the other options to confirm they are less likely or incorrect. 'Trauma' is the second most common cause. 'Oxytocics' are a treatment, not a cause. 'Precipitous labor' is a risk factor, not a direct cause.
Select the option that represents the highest incidence, which is 'Atonicity of uterus'.

Concept Tested & Keywords

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