anemia in pregnancy

Question 1

cut offs for anemia in pregnancy

Answer 1

1st tri: 11/33
2nd tri: 10.5/32
3rd tri: 11/33

for blacks: reduce cut offs by 0.8/2%

Question 2

physiologic considerations in pregnancy

Answer 2

• 50% increase in plasma volume
• 25% increase in RBC mass
• 2.3 g total iron stores
• 1 g for pregnancy
• 70% of boy’s iron is functional

Question 3

ddx for acquired causes of anemia? hereditary?

Answer 3

acquired

• iron deficiency
• folate/b12 deficiency
• blood loss
• autoimmune
• hemolytic anemia
• aplastic anemia
• malignancy
• durg-induced

hereditary

• sickle cell hemoglobinopathy
• thalassemias
• hereditary hemolytic anemia

Question 4

describe structure of hemoglobin, types of hemoglobin

Answer 4

four globin chains

• adult hemoglobin has 2 alpha chains, then:
• 2 beta chains (Hgb A)
• 2 delta chains (Hb A2)
• 2 gamma chains (Hb F) - predominates in fetus at 12-14 weeks

Question 5

what has highest sensitivity/specificity for iron deficiency anemia?

Answer 5

ferritin lower than 10-15 micrograms/L

Question 6

what type of inheritance is sickle cell anemia? what is the defect?

Answer 6

autosomal recessive

substitues valine for glutamic acid at #6 position on beta globin chain

Question 7

incidence of sickel cell trait, and dz in african americains?

Answer 7

1:12, 1:30

Question 8

4 components to acute pain crisis

Answer 8

• pulmonary infiltrate (vaso-occlusive disease)
• fever
• hypoxemia
• acidosis

Question 9

what types of hemoglobin are present in ss trait vs ss disease

Answer 9

ss trait (AS disease): higher percentage of HbA, asymptomatic
ss disease: virtually all Hb in HbS with little HbA2 and HbF

Question 10

what are maternal RFs with ss disease in pregnancy

Answer 10

• gHTN
• increased crises
• infections
• PTL
• PPROM

Question 11

fetal risks with ss disease in pregnancy

Answer 11

• IUGR
• IUFD
  therefore serial NSTs/US reasonable

Question 12

treatment sickle cell disease in pregnancy

Answer 12

• 4 g folic acid supplementation
• avoid triggers (cold, physical stress, dehydration, infection)
• no hydroxyurea (teratogenic)

Question 13

sickle cell- microcytic or normocytic?

Answer 13

normocytic

Question 14

what is thalassemia general pathophysiology?

Answer 14

• decrease in globin chain synthesis

- generally same management as normal prgegnancy

Question 15

what groups are at risk of thalassemia?

Answer 15

• southeast asian
• mediterranean
• west indies
• hispanic

Question 16

what are the types of alpha thalassemias and associated chromosomal abnormalities?

Answer 16

• chromosome 16, alpha genes encoded by 4 chains (aa/aa)
• if 1 gene absent, this is clinically insignificant
• if 2 gene’s absent, this is alpha thalassemia minor. there are two types
  1. cis, where both genes missing on same chromosome (i.e. aa/__). more common in southeast asian, middle eastern, west indies. more likely to have offspring with HbH disease
  2. trans, where genes are missing on each chromosome. (a_/a_). More common in africans.
• if 3 genes are missing- HbH disease. moderate hemolytic anemia seen
• if 4 genes absent - Bart’s Disease (alpha-thalassemia major). Fetal hydrops typically

Question 17

what are types of beta thalassemias and associated chromosomal abnormalities?

Answer 17

beta chain gene, chromosome 11 (2 genes)
typically reflected with HbA2 > 3.5%, and greater HbF

• beta thalassemia minor (heterozygous)
  low risk, minor anemia is typically the issue
• beta thalassemia major (homozygous)
  severe anemia, death typically within 10 years of life, pregnancy rare. it is reasonable to get pregnant if noral cardiac function, if they are on long term transfusion therapy with chelation and Hgb > 10

Question 18

how are thalassemias diagnosed?

Answer 18

DNA testing

- although beta thalassemia will have elevated HbF and HbA2; alpha thal will not

Question 19

what should any patient with a hgb-opathy be given?

Answer 19

4 g folic acid

Question 20

how are fetal thalassemias diagnosed?

Answer 20

amniocentesis/cvs - dna testing

Question 21

when is transfusion indicated in anemia in antepartum period?

Answer 21

Hgb <6; fetal oxygenation can be compromised

Question 22

if giving transfusion for sickle cell in antepartum period, what are goals?

Answer 22

HbS < 40%

Hgb > 10%

Question 23

what is differential for pt not responding to PO iron therapy?

Answer 23

• incorrect diagnosis
• concurrent medical disease
• malabsorption (concurrent antacid use, enteric coated formulations)
• ongoing bleeding (consider GI source)
• non compliance

Question 24

what is overall risk of anaphylaxis to IV iron? what formulation is highest risk?

Answer 24

1%. IV Fe dextran > IV Fe sucrose.