Clinical meaning
Obstetric hemorrhage involves unique physiological challenges: pregnancy increases blood volume by 40-50% (hypervolemic state), dilutional anemia masks true blood loss. Uterine blood flow at term is 500-700 mL/min, making atony catastrophic. Massive Transfusion Protocol (MTP) targets 1:1:1 ratio of pRBC:FFP:Platelets. Fibrinogen is the first coagulation factor depleted (critical threshold <200 mg/dL).
Diagnosis & workup
Diagnostics & workup: - Order CBC, coagulation studies (PT/PTT/fibrinogen), and type & crossmatch STAT - Order serial fibrinogen levels (first factor depleted; critical < 200 mg/dL) - Calculate Shock Index (HR/SBP): more sensitive than vitals alone in pregnancy - Order thromboelastography (TEG/ROTEM) for point-of-care coagulation assessment - Order lactate and base deficit for perfusion assessment - Order arterial blood gas for acid-base status - Order pelvic ultrasound to evaluate for retained products - Order quantitative blood loss measurement (not visual estimation)
Risk factors: - Uterine atony - Placenta accreta spectrum - Coagulopathy (DIC) - Uterine inversion - Prior uterine surgery - Prolonged oxytocin use - Grand multiparity - Chorioamnionitis