anemia in pregnancy; gestational anemia

Physiology

• gestational anemia (physiologic) results from an increase in plasma volume proportionately larger than the increase in erythrocyte production
  • this reduces viscosity of blood delivered to the placenta & fetus

Laboratory

• complete blood count (CBC)
  • blood hemoglobin > 10.5-11 g/dL
  • blood hemoglobin < 11 g/dLin the 1st trimester & < 10 g/dL in the 2nd & 3rd trimesters should prompt an investigation for causes of anemia
• iron studies*
• reticulocyte count
• serum vitamin B12, serum folate
• reticulocyte count
• anemia workup in pregnant women indicated for
  • marked anemia
  • other cytopenias
  • abnormal reticulocyte count
  • abnormal RBC indices

* USPSTF concludes not enough evidence to recommend either for or against screening for iron-deficiency anemia in asymptomatic pregnant women

Complications

• iron deficiency anemia during pregnancy has been associated with an increased risk of low birth weight, preterm delivery, & perinatal mortality.
• severe anemia with maternal hemoglobin (Hgb) levels < 6 g/dL has been associated with abnormal fetal oxygenation resulting in fetal heart rate abnormalities, diminished amniotic fluid volume, fetal cerebral vasodilatation, & fetal death

Management

• prenatal vitamins including folate 1 mg/day
  • folate requirement nearly doubles during pregnancy
  • folate supplementation reduces risk for neural tube defects
• iron supplementation
  • iron-deficiency anemia
  • empiric iron therapy appropriate for women with microcytosis, hyochromia & anisocytosis
  • iron supplementation decreases the prevalence of maternal anemia at delivery
  • USPSTF concludes not enough evidence to recommend either for or against routine iron supplementation in asymptomatic pregnant women
• maternal transfusion should be considered for severe anemia for the benefit of the fetus

More general terms

• pregnancy disorder; obstetric disorder; pregnancy complication
• anemia