Anemia in pregnancy

Anemia in pregnancy

Anemia is a condition in which the healthy red blood cells that carry oxygen to the tissue are insufficient to carry out normal activities and is diagnosed when Hb is less than 11g/dl.

During pregnancy, the blood volume is increased by 20-30%, and that will cause a mild anemia due to the dilution of blood and this will lead to a decrease in blood Hb down to 11.5g/dl which is considered to be normal during pregnancy. Therefore, the anemia during pregnancy is diagnosed when the Hb is less than 10.5g/dl and after delivery it's diagnosed when the Hb is less than 10 g/dl. 

Causes of anemia during pregnancy:

Physiological anemia:

This is caused by the increase in blood volume that will cause dilution of blood due to the decrease in the concentration of red blood cells, and this is normal during pregnancy.

Iron deficiency anemia:

It’s the most common cause of anemia during pregnancy. And it is caused if the woman does not have adequate iron stores before she becomes pregnant. The fetus uses her red blood cells to grow and develop.

Vitamin B12 deficiency:

Vitamin B12 is important for red blood cell formation and its deficiency will lead to anemia. this is common in vegans (those who don’t eat animal product). To prevent this, adding foods to your diet such as milk, meat, egg, and poultry can prevent vitamin B12 deficiency.

Folic acid deficiency:

Folic acid works with iron to help in the growth of cells, and usually is associated with iron deficiency anemia because both iron and folic acid are found in the same types of foods.


Thalassemia is an autosomal recessive disorder that is caused by missing, or variant genes, that are important in Hb synthesis. This will cause weakening and destruction of red blood cells. Women who are thalassemia carriers may be asymptomatic before pregnancy and may become symptomatic during pregnancy. In these cases, the father should be examined and they should be advised to consider genetic counselling as they may need some prenatal testing to make sure that the baby will not be affected. Chorionic villous sampling that is done usually at 11 weeks, includes removing a tiny piece of placenta for evaluation, and amniocentesis is another method that is done at around 16 weeks of pregnancy by taking some of the fluid from around the baby for evaluation.

Sickle cell anemia:

Sickle Cell Anemia is an inherited blood disorder that is characterized by defective hemoglobin that becomes stiff and sticky when they lose oxygen These cells tend to cluster and this will cause blockage of blood vessels and this is what causes pain and the complications of sickle cell anemia. Normally the hemoglobin life span is 120 days while the sickle cell's life span is only 15 days, and they are under risk of being destroyed in the spleen.

  • Risks of sickle cell anemia on pregnant women include:

    - Infections (including urinary tract and lungs)
    - Gall bladder stones
    - Heart failure

    Risks of sickle cell anemia on fetus:

    - Miscarriage
    - Preterm labor
    - Intrauterine growth restriction
    - Low birth weight
    - Stillbirth

Less common causes of anemia in pregnancy

- Leukemia
- Hemolytic anemia
- GI bleeding

Symptoms of Anemia:

• Fatigue
• Shortness of breath
• Pale skin, lips, nails, palm of hands.
• tachycardia

Investigations needed to diagnose anemia during pregnancy:

• Hemoglobin
• Ferritin ( if it was between 10-50 mcg/l it needs to be followed up and if it was less than 10 mcg/l then it needs treatment).
• Mean cell volume (MCV), if it is less than 86 this verifies a diagnose of iron deficiency anemia.
• Hemoglobin electrophoresis

Treatment of anemia in pregnancy:

This depends on the type of anemia and it includes;
• Identification of the type of anemia and treat the underlying cause
• Dietary advice
• Iron, folic acid and vitamin B12 supplements

Complications of anemia in pregnancy:

The mortality rate is 3-5 times higher in pregnant women that have anemia than those women who don’t have anemia, and the incidence of still birth is 6 times higher.

Last Update: 2011-09-01