Answer: Genital Tract Laceration (Option C)
In a patient with 1000 cc of postpartum bleeding and a firm, well-contracted uterus after vaginal delivery, genital tract laceration is the most common cause, as the firm uterus effectively rules out uterine atony. 1
Clinical Reasoning
The key to answering this question lies in the physical examination finding of a firm uterus, which fundamentally changes the differential diagnosis:
Why Not Uterine Atony (Despite Being Most Common Overall)?
- While uterine atony accounts for 70.6% of all postpartum hemorrhage cases overall 2 and up to 80% in some series 3, it presents with a soft, boggy uterus that fails to contract properly 1
- The American College of Radiology specifically states that when postpartum hemorrhage occurs with a firm, well-contracted uterus, genital tract trauma becomes the leading cause 1
- A firm uterus on examination effectively excludes uterine atony as the diagnosis 1
Why Genital Tract Laceration is Correct Here?
- The American College of Radiology Appropriateness Criteria identifies vaginal lacerations as causes of bleeding that can be diagnosed by history and physical examination when the uterus is firm 1
- The clinical approach algorithm for postpartum hemorrhage specifically directs clinicians to assess uterine tone first, and if the uterus is firm, to thoroughly inspect the genital tract for lacerations 1
- Genital tract trauma accounts for 16.9% of postpartum hemorrhage cases overall 2, but becomes the primary consideration when uterine tone is normal 1
Why Not the Other Options?
- Retained products of conception (Option D): While retained placenta accounts for 16.4% of postpartum hemorrhage cases 2, the question states placental delivery was completed
- Coagulopathy (Option B): Accounts for only 2.7% of postpartum hemorrhage cases 2 and typically develops following cardiovascular collapse or as a secondary phenomenon 4
Clinical Approach
The systematic evaluation should proceed as follows:
- First: Assess uterine tone by palpation 1
- If firm: Perform thorough inspection of the cervix and vagina for lacerations 1, 4
- If soft/boggy: Diagnose uterine atony and initiate uterine massage with uterotonics 4
- If bleeding persists despite firm uterus and no visible lacerations: Verify complete placental delivery and assess for coagulopathy 1
Common Pitfall to Avoid
Do not assume uterine atony is the cause simply because it is statistically most common overall—the physical examination finding of uterine tone is the critical discriminating factor that shifts the differential diagnosis toward genital tract trauma 1