You know they could throw us a bone or something... Tell us the uterus is boggy at least, or hard, or ANYTHING AT ALL REALLY....

• Woman with complicated/prolonged delivery with excessive postpartum bleeding who does not have retained placenta, genital tract trauma or history of coagulopathy, and therefore most likely has uterine atony (most common cause of postpartum bleeding and commonly seen after prolonged/difficult delivery)
• Causes of post-delivery bleeding is 4 T’s: (1) aTony (most common) (2) Trauma (3) Thrombin (coagulopathy) (4) Tissue (retained placenta, etc.)

https://step-prep.org/tutoring/

This presentation really could be either retained placental tissue or uterine atony. i think the key with these nbme questions is to go with the most likely diagnosis, and the most common cause of post partum hemorrhage is uterine atony

"At times the bulk of the placenta will deliver spontaneously or manually, but small portions or an accessory lobe may be retained. This may be suspected when the placenta appears fragmented after delivery or when there is ongoing heavy uterine bleeding. In this situation, the uterine cavity may be evaluated with manual exploration or with ultrasound. The utility of ultrasound in this situation has yet to be established, with a focal endometrial mass, particularly with Doppler flow, being the findings of interest. In one study of routine ultrasound immediately after vaginal delivery, the sensitivity for diagnosing retained placental fragments was only 44% with a positive predictive value (PPV) of 58%" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6789409/#S0006title