Which among the following is the commonest cause of postpaum haemorrhage?
**Core Concept**
Postpartum hemorrhage (PPH) is a leading cause of maternal mortality worldwide, characterized by excessive bleeding following delivery. The underlying cause of PPH is often related to uterine atony, which refers to the failure of the uterus to contract effectively after delivery.
**Why the Correct Answer is Right**
Uterine atony is the most common cause of PPH, accounting for approximately 80-90% of cases. This occurs when the uterus is unable to contract and compress the blood vessels in the uterus, leading to excessive bleeding. The lack of effective uterine contractions can be due to various factors, including excessive uterine distension during labor, inadequate uterine massage, or the use of certain medications such as tocolytics.
**Why Each Wrong Option is Incorrect**
**Option A:** Retained placental tissue is a less common cause of PPH, accounting for around 5-10% of cases. While it can lead to significant bleeding, it is not the most common cause.
**Option B:** Uterine rupture is a rare but life-threatening cause of PPH, often associated with previous uterine surgery or trauma. However, it is not the most common cause.
**Option C:** Coagulopathy, such as disseminated intravascular coagulation (DIC), can contribute to PPH, but it is not the most common cause.
**Clinical Pearl / High-Yield Fact**
To prevent uterine atony and PPH, it is essential to ensure effective uterine contractions after delivery through massage and the use of oxytocin. This can be initiated immediately after delivery, and continuous uterine massage should be continued for at least 10-15 minutes.
**Correct Answer:** C. Uterine atony.