Placental Abruption

Dark red vaginal bleeding with a rigid, board-like abdomen in the third trimester signals a placental emergency — but up to 20% of abruptions have no visible bleeding at all.

Placental abruption is the premature separation of a normally implanted placenta from the uterine wall after 20 weeks' gestation. Separation triggers retroplacental hemorrhage, which may be revealed (vaginal bleeding), concealed (blood trapped behind the placenta), or mixed. The hallmark triad is dark red vaginal bleeding, uterine rigidity (board-like or hypertonic uterus), and abdominal or back pain that is sudden and constant — not intermittent like contractions. Fetal heart rate tracings typically show late decelerations or bradycardia reflecting uteroplacental insufficiency. Risk factors include chronic hypertension, preeclampsia, cocaine or methamphetamine use, abdominal trauma, prior abruption, and premature rupture of membranes. Severity ranges from marginal (grade 1, mild) to complete separation (grade 3) with fetal demise and potential maternal DIC. Nursing priorities center on continuous fetal monitoring, frequent vital signs, monitoring uterine tone, two large-bore IVs, labs (CBC, fibrinogen, coagulation studies, type and crossmatch), and strict intake and output. A declining fibrinogen level below 200 mg/dL signals developing DIC. Delivery — often emergency cesarean — is the definitive treatment for moderate-to-severe abruption.

Key Distinctions

Don't confuse abruption (painful, rigid uterus, dark bleeding) with placenta previa (painless, bright red bleeding, soft uterus) — pain and uterine tone are the differentiators. Students forget that concealed hemorrhage means the visible blood underestimates true blood loss; the patient can be in hypovolemic shock with minimal external bleeding. A falling fibrinogen is an earlier DIC indicator than rising PT/INR.

Clinical Pearl

Painful + rigid + dark = abruption. Painless + soft + bright = previa. When the uterus feels like a rock and the patient is in agony, think separation.