Sickle Hemoglobinopathies in Pregnancy

Contributor: John V. Dacus, MD
Last Update: 8/1/2007

Worldwide, there are approximately 270 million people who are heterozygous for hereditary abnormalities of hemoglobin and 300,000 who are homozygous or compound heterozygous.  Hemoglobinopathies result in either production of abnormal hemoglobins or reduction or absent normal globin chains.

Normal Adult Hemoglobin

Hgb A            a2B2             95-97%
Hgb A2          a2d2               < 3.5%
Hgb F            a2g2                < 3%

Short arm of chromosome 16 contains genes coding for a chains.  Short arm of chromosome 11 contains genes coding for B chains.

Sickle cell diseases comprise:

1) Hgb AS      2) Hgb SS       3) Hgb sickle B Thal       4) Hgb SC

Diagnoses of Sickle Hemoglobinopathies require hemoglobin electrophoresis 
Screen all African Americans with Hgb electrophoresis.

• Sickle cell trait (Hgb AS) demonstrates the amount of hemoglobin A greater than the amount of S (usually 60% to 40%).
• Sickle cell anemia  (Hgb SS) demonstrates virtually no Hgb A on electrophoresis.
• Sickle B Thalassemia-  Hemoglobin electrophoresis shows Hgb S percentage greater than Hgb A and increased percentage of A2 over 3.5%.
• Hemoglobin SC demonstrates virtually no Hgb A and 2 spikes corresponding to S+C.

Antepartum Management of Sickle (Hgb SS, Hgb SC & Hgb Sickle B Thal) Hemoglobinopathies

• Patient will be referred to genetic counseling.  Father of the baby may be tested at the Health Department via the Barksdale Foundation.  If possible, preconception counseling may be done by the genetics department.
• Give pneumococcal vaccine and influenza vaccine for those who have not received these within 12 months.
• Prescribe Folic acid 4 milligrams per day throughout pregnancy.
• Obtain urine culture and sensitivity each trimester.  Monitor for infection (urinary tract infection, pyelonephritis, and acute chest syndrome) at each visit.
• Obtain hemoglobin and hematocrit each trimester or as indicated.
• Continue co-management with hematology.
• Monitor for preeclampsia.
• Obtain hemoglobin and hematocrit each trimester or as indicated.
• Avoid iron therapy unless low serum ferritin and/or < 16% ratio of serum iron to total iron binding capacity.
• Following anatomic fetal survey at 18-20 weeks, obtain obstetric ultrasound at 28-30 weeks for growth and as needed for low fundal height.
• Encourage patient to avoid cold environment, dehydration, stress, heavy physical exercise which may precipitate painful crisis.
• Begin antenatal fetal testing at 34 weeks once weekly.  If IUGR or preeclampsia occurs, begin twice weekly testing.

Intrapartum Management

• Intrapartum administration of maternal O2
• Epidural anesthesia
• Adequate IV fluid Intrapartum 125-150 cc/hr
• Cesarean section for obstetric indications only
• Avoid prolonged pushing in second stage of labor

Management of Pain Crisis

• Supplemental O2
• IV fluids – 125-150 cc/hr D5RL
• Opiates – orally, intramuscularly or intravenously (Morphine, Demerol)
• Search for underlying infection, dehydration or other stressors
• Red blood cell transfusions if symptomatic anemia or to break repetitive crisis
• Consider partial exchange transfusion if crisis recalcitrant to usual methods only in concert with hematology.

Partial Exchange Transfusion Protocol

• Type and cross buffy-coat poor washed CMV negative red cells
• 300 cc D5RL IV over 1 hour
• Phlebotomize 500 cc blood
• Give 2 units packed RBC’s
• Repeat procedure and allow overnight equilibration
• Obtain Hgb and Hgb A concentration (Hgb electrophoresis in AM)
• Repeat procedure if necessary to reach a Hgb of 10 and Hgb A of close to 55-60%

PostPartum

• Early ambulation
• Appropriate hydration
• Compression stockings
• Progesterone only oral contraceptives, Progestin containing IUD,  Depo Provera IM or permanent sterilization may be offered as contraception.

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References

1. Morrison JC, Schnaeider JM, et al.  Prophylactic transfusions in pregnant patients with sickle hemoglobinopathies:  Benefits versus risk. Ob & Gyn: 1980;56, no.3:274-280.
2. Kosky M, Bwad L, et al.  Prophylactic red-cell transfusions in pregnant patients with sickle cell disease.  N Engl J Med 1980;319:121-125
3. 2007 Compendium.  Vol II: Practice bulletins.  Hemoglobinopathies in pregnancy; 802-809.
4. Clinical obstetrics and gynecology. Pregnancy complicated by sickle hemoglobinopathy.  Lippincott-Raven Publishers.  Vol 38, no. 3:1995;472-484.