Rosen & Barkin's 5-Minute Emergency Medicine Consult (412 page)

• Symptoms of labor:
  
  • Intermittent low abdominal pain with or without low back pain
    
  • Occurring regularly at least every 5 min
    
  • Lasting 30–60 sec
    
• Preterm labor is of sufficient frequency and intensity to bring about changes in dilation or effacement of cervix before 37 wk
  
• Labor is not associated with vaginal bleeding:
  
  • Patients with 3rd-trimester abdominal pain or vaginal bleeding should raise suspicion of placenta previa or placental abruption
    
• Sudden release of clear fluid from vagina or feeling of constant perineal wetness can represent rupture of membranes:
  
  • This is not always associated with labor but often leads to onset of labor
    

• Gestational age
  
• Prenatal care
  
• Previous pregnancies:
  
  • Complications
    
  • C-section
    
• Recent infections
  

• Assess fundal height:
  
  • Centimeters from pubic bone to top of uterus
    
  • Correlates with number of weeks after 2nd trimester
    
  • Can help determine gestational age if unknown
    
• Sterile pelvic exam to assess cervical dilation and effacement
  

• Patients presenting in possible labor should have
  immediate sterile pelvic exam
  to assess dilation, effacement of cervix, and possibility of imminent delivery.
  
• Bimanual pelvic exam should NOT be done in 3rd-trimester patient with vaginal bleeding until US can be done to assess for placenta previa or placental abruption.
  
• Patients with suspected rupture of membranes should have sterile speculum exam with visual exam of cervix and collection of fluid from vaginal area
  
• Suggestive of rupture of membranes:
  
  • Presence of
    ferning
    when fluid is allowed to dry on a slide
    
  • Presence of
    pooling
    of fluid in vagina
    
  • Change of color of litmus paper
    from yellow to blue
    
• Patients with preterm labor and cervical changes should have urinalysis with culture and cervical cultures
  
• Fetal monitoring should be initiated
  

• If patient is in labor, CBC, type, and screen should be sent.
  
• Urinalysis for proteinuria
  
• In patients with no prenatal care, obtain Rh factor and antibody screen.
  
• Cervical cultures and urine culture in patients with preterm labor
  

• Not generally needed
  
• 3rd-trimester patients with abdominal pain and vaginal bleeding should have emergent US to evaluate for placenta previa or abruption.
  

• Braxton Hicks contractions (false labor) are irregular uterine contractions without associated cervical changes:
  
  • Contractions can be every 10–20 min
    
• Round uterine ligament pain, musculoskeletal back pain
  
• Other common causes of abdominal pain, such as appendicitis, ovarian cyst, diverticulitis, nephrolithiasis, UTI
  

TREATMENT

• Emergency medical services personnel should place patients in labor on oxygen and in left lateral recumbent position to maximize delivery of oxygen to uterus
  
• Maternal transport of high-risk obstetric patients before delivery results in improved outcomes instead of transfer of neonate after delivery
  
• Air transport of high-risk obstetric patients has been shown to be beneficial and cost effective
  
• Patients in labor who are transported by aircraft should have high-flow oxygen available in the event of cabin decompression at high altitudes
  

If delivery is imminent (presenting part visible), prepare for immediate vaginal delivery in ED (see “Delivery, uncomplicated”)

• Unless delivery is imminent, patient should be sent directly to the labor and delivery (L&D) unit
  
• If transport to L&D will be delayed, or if transfer to another facility is necessary, these steps should be taken:
  
  • Consider IV antibiotics for unknown group B Streptococcus status
    
  • IV hydration with 1 L NS or 5% dextrose in lactated Ringer over 30–60 min
    
  • Maternal monitoring
    
  • Fetal monitoring
    
  • If labor needs to be arrested (premature fetus), begin a tocolytic such as β-agonist terbutaline or magnesium sulfate:
    
    • Magnesium toxicity is suggested by loss of deep tendon reflexes
      
    • High doses of magnesium can cause cardiac dysrhythmias and respiratory depression.
      

• Magnesium sulfate: 4–6 g IV over 30 min, followed by 2–6 g/hr
  
• Terbutaline: 0.25 mg SC; may repeat same dose in 30 min
  

FOLLOW-UP

• All patients in labor who are not at risk for imminent delivery should be admitted to L&D
  
• Preterm patients in labor demand immediate obstetric consultation and should be admitted to L&D for further treatment
  

Patients with false labor may be discharged only after obstetric consultation, confirmation of fetal well-being, and close follow-up is arranged:

• False labor may progress to true labor
  

• If vaginal bleeding is present, must rule out placental abruption or previa
  
• Do not perform a digital exam if bleeding is present
  
• Pelvic exam must be sterile in a patient in labor
  
• False labor may progress to true labor
  

• Berghella V, Baxter JK, Chauhan SP. Evidence-based labor and delivery management.
  Am J Obstet Gynecol
  . 2008;199:445–454.
  
• DeCherney A, Nathan L, Goodwin TM, et al., eds.
  Current Diagnosis and Treatment, Obstetrics and Gynecology
  . 10th ed. New York, NY: McGraw-Hill; 2007.
  
• Liao JB, Buhimschi CS, Norwitz ER. Normal labor: Mechanism and duration.
  Obstet Gynecol Clin North Am
  . 2005;32:145–164.
  
• Wilson W, Taubert KA, Gewitz M, et al. Prevention of infective endocarditis: Guidelines from the American Heart Association: A guideline from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group.
  Circulation.
  2007;116:1736–1754.
  
• Wolfson AB, Hendey GW, Ling LJ, et al., eds.
  Harwood Nuss’ Clinical Practice of Emergency Medicine
  . 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2010.
  

See Also (Topic, Algorithm, Electronic Media Element)

• Delivery, Uncomplicated
  
• Placental Abruption
  
• Placenta Previa
  

CODES

• V22.0 Supervision of normal first pregnancy
  
• V22.1 Supervision of other normal pregnancy
  
• V23.9 Supervision of unspecified high-risk pregnancy
  

BASICS

• Inflammatory disorder of the inner ear
  
• Inflammation decreases afferent firing from the labyrinth
  
  • CNS interprets the decreased signal as head rotation away from the diseased labyrinth
    
  • The imbalance in firing from the labyrinth results in spontaneous nystagmus with fast phase away from the pathologic side
    
• Form of unilateral vestibular dysfunction that typically cause balance disorders and vertigo, and may be associated with hearing loss and tinnitus
  
• Peak onset 30–60 yr old
  
• Associated with upper respiratory tract infection in 50% of patients
  
• Symptoms predominantly with head movement but can persist at rest
  
• Recovery phase gradual over weeks to months