Updated: 2/19/2020

Rh Disease

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Snapshot
  • A 30-year-old G2P1 woman presents to the emergency room with contractions at 37 weeks. She previously had a baby boy via spontaneous vaginal delivery without complications. She had this delivery done in a foreign country, and obstetric records are not available. Her prenatal care has also been limited. On fetal ultrasound, it is noted that the fetus has ascites and soft tissue edema. She is immediately prepped for delivery.
Introduction
  • Overview
    • Rh hemolytic disease of the newborn is caused by Rh incompatibility
    • maternal anti-Rh IgG antibodies cross the placenta and destroy fetal Rh-positive red blood cells
  • Epidemiology
    • incidence
      • 15% of the population is Rh-negative
    • risk factors
      • history of prior blood transfusion
      • previous pregnancy
      • mother is Rh-negative, and father is Rh-positive or unknown
      • prior administration of Rh IgG (RhoGam)
      • history of invasive obstetric procedures
  • Pathogenesis
    • mechanism    
      • Rh factor is a red blood cell antigen
      • when a Rh-negative mother is pregnant with a Rh-positive fetus, the mother is exposed to Rh-positive red blood cells and leads to maternal antibody production (IgG) against the foreign Rh antigen
      • as IgG can cross the placenta, subsequent pregnancy with Rh-positive fetus will result in fetal alloimmune induced hemolytic anemia
      • development of antibody depends on volume of transplacental crossover of red blood cells, concurrent presence of ABO incompatibility, and extent of maternal immune response
      • breakdown of red blood cells causes elevation of bilirubin
Presentation
  • Symptoms
    • hemolytic anemia
  • Physical exam
    • inspection
      • jaundice
      • pallor
Imaging
  • Fetal ultrasound
    • indication
      • suspected Rh incompatibility
    • findings
      • fetal ascites and edema
Studies
  • Serum labs
    • hyperbilirubinemia
    • low hematocrit
    • elevated reticulocyte count
    • positive direct Coombs test
  • Rosette test
    • to detect fetal-maternal hemorrhage
  • Kleihauer-Betke test
    • if Rosette test is positive, can conduct this test
    • measures fetal red blood cells in utero in maternal circulation to determine dose of RhoGAM
Differential
  • ABO incompatibility
    • key distinguishing factor
      • typically less severe
Treatment
  • Medical
    • maternal anti-D immune globulin (Rh IgG or RhoGAM) administration
      • indication
        • only if mother is Rh-negative and has not been sensitized previously, given at 28th week of pregnancy, if possible, and within 72 hours after birth
        • external cephalic version
        • amniocentsis
        • ectopic pregnancy
    • exchange transfusion
      • indications
        • erythroblastosis fetalis
        • hydrops fetalis
        • kernictus
Complications
  • Kernicterus secondary to hyperbilirubinemia
    • loss of Moro reflex
    • posturing
    • poor feeding
    • seizures
  • Erythroblastosis fetalis
    • most severely, can manifest as hydrops fetalis with high output cardiac failure, edema, and death
    • indication for immediate delivery and exchange transfusion
 

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Questions (2)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
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(M2.OB.17.4817) A 31-year-old G2P1001 presents to the labor floor for external cephalic version (ECV) due to breech presentation at 37 weeks gestation. Her pregnancy has been complicated by an episode of pyelonephritis at 14 weeks gestation, treated with intravenous ceftriaxone. The patient has not had urinary symptoms since that time. Otherwise, her prenatal care has been routine and she tested Rh-negative with negative antibodies at her first prenatal visit. She has a history of one prior spontaneous vaginal delivery without complications. She also has a medical history of anemia. Current medications include nitrofurantoin for urinary tract infection suppression and iron supplementation. The patient’s temperature is 98.5°F (36.9°C), pulse is 75/min, blood pressure is 122/76 mmHg, and respirations are 13/min. Physical exam is notable for a fundal height of 37 centimeters and mild pitting edema in both lower extremities. Cardiopulmonary exams are unremarkable. Bedside ultrasound confirms that the fetus is still in breech presentation. Which of the following should be performed in this patient as a result of her upcoming external cephalic version? Review Topic | Tested Concept

QID: 109396
1

Complete blood count

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Urinalysis

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Fibrinogen level

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Urine protein to creatinine ratio

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Rhogam administration

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(M2.OB.15.4672) A 29-year-old G1P0 female at 32 weeks gestation presents to the emergency department with vaginal bleeding. She has had minimal prenatal care to-date with only an initial visit with an obstetrician after a positive home pregnancy test. She describes minimal spotting that she noticed earlier today that has progressed to larger amounts of blood; she estimates 30 mL of blood loss. She denies any cramping, pain, or contractions, and she reports feeling continued movements of the baby. Ultrasound and fetal heart rate monitoring confirm the presence of a healthy fetus without any evidence of current or impending complications. The consulted obstetrician orders blood testing for Rh-status of both the mother as well as the father, who brought the patient to the hospital. Which of the following represents the best management strategy for this situation? Review Topic | Tested Concept

QID: 107196
1

If mother is Rh-negative and father is Rh-positive then administer RhoGAM

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If mother is Rh-negative and father is Rh-negative then administer RhoGAM

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3

If mother is Rh-positive and father is Rh-negative then administer RhoGAM

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4

If mother is Rh-negative and father is Rh-positive, RhoGAM administration is not needed

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5

After 28 weeks gestation, administration of RhoGAM will have no benefit

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