Hey there! Postpartum Hemorrhage (PPH) is one of those high-stakes topics that shows up on almost every OB/GYN rotation and USMLE Step exam. It’s definitely something you want to have down cold, not just for the boards, but for real-life clinical practice too.

To keep it simple, we always start with the 4 Ts, which cover about 99% of the causes you'll see.

The Causes: The 4 Ts

Mnemonic: The 4 Ts of PPH

1. Tone (Uterine Atony): The most common cause (~80%). The uterus is "boggy" and fails to contract down to compress the spiral arteries.
2. Tissue: Retained products of conception (placenta, membranes, or clots).
3. Trauma: Lacerations (cervical, vaginal, perineal), uterine rupture, or uterine inversion.
4. Thrombin: Coagulopathies like DIC, von Willebrand disease, or HELLP syndrome.

Risk Factors

While PPH can happen to anyone, keep an eye out for these "red flags" in a patient's history:

• Overdistended uterus: Multiple gestations, polyhydramnios, or macrosomia (stretches the muscle fibers too much).
• Muscle exhaustion: Prolonged labor or rapid (precipitous) labor.
• Infection: Chorioamnionitis.
• Medications: Magnesium sulfate (it's a muscle relaxant!) or halogenated anesthetics.
• History: Previous PPH or operative vaginal delivery (forceps/vacuum).

I'll pull up a helpful visual that breaks down these causes and the initial management steps for you.