Iron Deficiency in Pregnancy

Iron deficiency is a common condition during pregnancy, affecting over 30% of pregnancies in Canada. During pregnancy, as the pregnant person’s blood volume expands and the fetus grows, their ferritin levels decrease.

Iron Deficiency & Adverse Pregnancy Outcomes

Iron deficiency in pregnancy is associated with several adverse pregnancy outcomes including:

• Low birth weight

• Preterm birth

• Small for gestational age infants

• Increased risk of postpartum hemorrhage

• Increased risk of postpartum depression

• Impaired fetal neurodevelopment

Signs & Symptoms of an Iron Deficiency

Symptoms of iron deficiency during pregnancy include:

• Fatigue

• Weakness

• Dizziness

• Irritability

• Decreased stamina

• Hair loss

• Shortness of breath

• Reduced exercise tolerance

• Increased susceptibility to infection

The above symptoms are very non-specific though, and may be dismissed as common pregnancy symptoms. Because iron deficiency is so common though, testing is quite important to rule this out as a cause for the above symptoms.

What Should be Tested?

To determine if an iron deficiency exists or if an iron deficiency anemia exists the following should be tested:

• Ferritin

• Hemoglobin (which is part of a complete blood count)

Iron Deficiency vs. Iron Deficiency Anemia

Iron deficiency occurs when iron stores in the body fall below ideal levels, but anemia is not yet present. This is typically defined as having a ferritin level below 35 μg/L. Hemoglobin levels are still within the normal range.

Iron deficiency anemia (IDA) is a more advanced stage where the iron deficiency has progressed to the point that a person’s iron status is too low to meet the bone marrow's demands for red blood cell production. Both ferritin and hemoglobin levels are below the reference range.

When Does Testing Happen?

Ideally, I love when my clients have their ferritin and hemoglobin prior to pregnancy to get a baseline. However, that’s not always possible.

Ferritin and hemoglobin are usually tested as part of the first trimester blood tests. In this instance, ferritin may be artificially elevated. Ferritin is an acute phase reactant, meaning its levels can increase in response to inflammation, even during normal pregnancies.

Ferritin and hemoglobin re-tested later in pregnancy alongside the gestational diabetes test (around 24-28 weeks gestation). This is the point in time where most pregnant people are diagnosed as iron deficient or anemic, and this is when most supplementation occurs.

Iron Supplementation

Most prenatal vitamins do not contain enough iron to treat deficiency. In addition, it can take a long time to raise levels - especially as levels decrease as pregnancy progresses. In most cases, this isn’t the time to focus on diet and consuming more animal protein or plant-based sources of iron. Supplementation is the first-line treatment to correct the deficiency.

In some cases, IV iron is needed to quickly raise levels in the second and third trimester, if deemed appropriate by your obstetrical care provider.

Moreover, retesting ferritin and hemoglobin after 6 weeks postpartum will help determine where the levels are at and if supplementation can stop or should be continued.

Next Steps

Iron deficiency is important to recognize during pregnancy due to its impacts on adverse pregnancy outcomes, as well as its impact on mental health in the postpartum.

If you’re looking for support during your pregnancy, please don’t hesitate to book an appointment with me.