Rosen & Barkin's 5-Minute Emergency Medicine Consult (548 page)

Painless
vaginal bleeding in pregnancy after 20 wk is placenta previa until proven otherwise

• Painless bright red vaginal bleeding in 70%
  
• Uterine contraction in 20%
  
• Common incidental finding on US in 2nd trimester (6% at 16–18 wk)
  
• 1st episode of bleeding typically occurs at 27–32 wk
  
• Bleeding may range from minor to massive; number of bleeding episodes does not correlate with degree of placenta previa
  
• Inciting factors—usually no cause; recent intercourse or heavy exercise may contribute
  
• Initial bleeding is often self-limited and not lethal, but often recurs
  

• Never do a digital exam or instrument probe of the cervix in 2nd-trimester vaginal bleeding until placenta previa is ruled out
  
• Sterile speculum exam can be safely performed prior to US to identify if blood is from the os, a vaginal lesion, or hemorrhoids
  
• Blood seen at patient’s feet is a sign of heavy bleeding
  
• Hypotension and tachycardia may indicate hemorrhagic shock
  
• Fetal heart tones should be monitored along with other vital signs
  

Vaginal ultrasonography is the diagnostic procedure of choice

• CBC, platelets
  
• Type and screen; upgrade to cross-match if transfusion is indicated
  
• Kleihauer–Betke (KB)—detects >5 mL of fetal cells in maternal circulation (it takes only 0.1 mL to sensitize mother if Rh negative)
  
• If coagulopathy suspected (rare): Prothrombin time/partial thromboplastin time, fibrin-split products, fibrinogen (<300 mg/dL is abnormal)
  
• Rh status
  

• Transabdominal US: 93–98% accurate:
  
  • False negative: Obesity, posterior or lateral placenta, fetal head over cervical os
    
  • False positive: Overdistended bladder
    
  • No sufficient accuracy for placenta previa position, need to obtain transvaginal US if placenta previa is detected or uncertain findings
    
• Transvaginal US: 100% accurate:
  
  • Vaginal probe does not exacerbate bleeding
    
• Color flow Doppler US: Used to determine placenta accreta
  
• MRI: May be useful in evaluating placental abnormalities such as accreta and percreta
  

• Placenta abruption (may occur concurrently)
  
• Uterine rupture
  
• Fetal vessel rupture
  
• Cervical/vaginal trauma
  
• Cervical/vaginal lesions
  
• Bleeding disorder
  
• Spontaneous abortion
  
• “Bloody show” of labor
  

TREATMENT

• Patient with vaginal bleeding at >24 wk should be transported to a facility that can handle high risk and premature delivery
  
• Place patient in left lateral recumbent position if hypotensive in 2nd half of pregnancy
  
• O
  ₂
  and IV as with other patients
  

• Resuscitation for hemorrhagic shock as with any source with monitoring of fetus and higher cut off of blood transfusion
  
• ABCs
  
• 2 large-bore IVs with normal saline (NS) or lactated Ringer (LR) for resuscitation
  
• Left lateral recumbent position if hypotensive in 2nd half of pregnancy
  
• Fluid resuscitation
  
• Blood transfusion for hematocrit (Hct) <30 or hypotension not responding to fluids
  
• Fresh-frozen plasma if coagulopathy
  
• Fetal monitoring (heart rate <120 or >160 bpm is abnormal)
  
• Immediate OB consultation for symptomatic patients
  

• Emergent OB consultation for patients with active bleeding
  
• Volume resuscitation with 2 large-bore IVs with NS or LR
  
• Blood transfusion to keep Hct 30–35%
  
• RhoGAM if mother is Rh negative
  
• Fetal monitoring
  
• Keep NPO and on bed rest until considered stable by OB
  
• Magnesium sulfate only for contractions of preterm labor when delivery is not recommended
  
• Antenatal steroids (betamethasone) at 24–34 wk to stimulate prenatal lung maturity
  
• Emergency C-section or delivery for continued bleeding or fetal compromise
  

• RhoGAM: 1 vial (300 μg) IM if not already given at 28 wk; may need >1 vial if KB indicates >15 mL of fetal RBS
  
• Magnesium sulfate: 6 g IV over 20 min, then 2–4 g/h; adjust to contractions
  
• Betamethasone: 12 mg IM q24h × 2 doses
  

FOLLOW-UP

• Active bleeding placental previa is a potential obstetric emergency, and all patients should be admitted
  
• Select patients may be managed on outpatient basis if bleeding is resolved. In consultation with OB
  

• Asymptomatic patients
  
  • Bed rest is not necessary. Avoid strenuous physical activity. Report bleeding or contractions
    
  • <20 wk and placenta not over the os: No special follow up necessary
    
  • <20 wk and placenta 0–20 mm: Repeat US at 28 wk
    
  • Placenta >20 mm over os is unlikely to resolve. C-section at 36–37 wk
    
  • Pelvic rest (no intercourse or tampons in vagina) if placenta previa found after 28 wk or at any time if associated with bleeding
    
• 70% of patients will have a 2nd episode of bleeding
  

Patients with incidental finding of placenta previa found at <20 wk will need outpatient US to determine migration of placenta

• Do not perform digital vaginal exam if suspect vaginal bleeding after 2nd trimester. Do US first
  
• Sterile speculum exam and transvaginal US are safe and do not increase bleeding
  
• Painless vaginal bleeding after 20 wk is placenta previa until proven otherwise
  
• Painful vaginal bleeding after 20 wk is placental abruption until proven otherwise
  
• The 2 above conditions can occur simultaneously
  

• Cunningham FG, Leveno KJ, Bloom SL, et al.
  Williams’ Obstetrics
  . 23rd ed. New York, NY: McGraw-Hill; 2009.
  
• DynaMed. Placenta previa. 2009. Available at
  http://www.DynamicMedical.com
  
• Hacker NF, Gambone JC, Hobel CJ.
  Hacker and Moore’s Essentials of Obstetrics and Gynecology
  . 5th ed. Philadelphia, PA: WB Saunders; 2010.
  
• Lockwood CJ, Russo-Stieglitz K. Clinical manifestations and diagnosis of Placenta Previa.
  UpToDate
  ; Wolters Kluwer; 2012. Available at
  http://www.uptodate.com/patients/content/topic.do?topicKey=∼18112/pmocgerp3
  
• Marx JA, Hockberger RS, Walls RM, et al.
  Rosen’s Emergency Medicine: Concepts and Clinical Practice
  . 7th ed. St. Louis, MO: Mosby; 2009.
  
• Scott JR, Gibbs RS, Karlan BY, et al.
  Danforth’s Obstetrics and Gynecology
  . 10th ed. Philadelphia, PA: Lippincot Williams & Wilkins; 2008.
  

See Also (Topic, Algorithm, Electronic Media Element)

Placental Abruption

CODES

• 641.00 Placenta previa without hemorrhage, unspecified as to episode of care or not applicable
  
• 641.01 Placenta previa without hemorrhage, delivered, with or without mention of antepartum condition
  
• 641.10 Hemorrhage from placenta previa, unspecified as to episode of care or not applicable
  

BASICS

• Plant exposure is 1 of the most common reasons to contact the poison center
  
• Majority of cases involve unintentional ingestion in children <6 yr old.
  

Identification of ingested plant species should be attempted whenever possible.