Pregnancy, Iron & Ferritin: Why “Normal for Pregnancy” Isn’t the Whole Story

If you're pregnant, especially heading into your third trimester, you may have been told

that it's completely normal for hemoglobin, hematocrit and other red blood cell markers to decrease as pregnancy progresses. There is truth to that.

During pregnancy, plasma volume expands significantly. Because plasma volume increases more than red blood cell mass, blood becomes naturally more diluted. This is sometimes called the physiologic anemia of pregnancy.

But there is an important distinction:

A normal pregnancy related change in hemoglobin does not mean we should ignore depleted iron stores.

As delivery approaches, your body is preparing for one of the most nutritionally demanding events it will experience. You are supporting your own expanded blood volume, your placenta, your growing baby and your baby's developing iron stores.

And then comes delivery, where some blood loss is expected.

That makes pregnancy a particularly important time to pay attention to iron status.

Ferritin Matters Too

Hemoglobin tells us whether you currently have enough functioning red blood cells to carry oxygen.

Ferritin gives us information about your stored iron.

Think of hemoglobin as the money in your checking account and ferritin as part of your savings account. It is possible to maintain an acceptable hemoglobin while gradually draining your iron reserves. By the time hemoglobin becomes clearly abnormal, iron depletion may already be well underway. That is why I prefer looking beyond hemoglobin alone when evaluating iron status.

Depending upon the individual, testing may include:

• CBC with hemoglobin, hematocrit, RBC indices and RDW

• Ferritin

• Serum iron

• TIBC or transferrin

• Iron saturation

• Sometimes B12 and folate, particularly when the blood count suggests there may be more than iron involved

Ferritin also behaves as an acute phase reactant, meaning inflammation can sometimes make ferritin appear higher than the body's true usable iron status would suggest. Labs should therefore be interpreted together rather than relying on one number.

Why Iron Needs Increase During Pregnancy

Pregnancy requires significantly more iron than the nonpregnant state. Iron supports increased maternal red blood cell production, placental development and fetal growth.

The recommended dietary allowance increases from 18 mg per day for most nonpregnant women ages 19 to 50 to 27 mg per day during pregnancy.

For this reason, diet matters tremendously, but women who are already entering pregnancy with low ferritin may have difficulty rebuilding their stores through food alone.

The goal should not simply be:

"Can we keep hemoglobin barely within the pregnancy reference range?"

A better question is:

"Does this mother have adequate iron available for pregnancy, delivery and postpartum recovery?"

Building Iron Through Food

Food should be one of the foundations of maintaining healthy iron stores. Some of the most useful iron rich foods include:

Heme iron sources

• Beef

• Lamb

• Dark meat poultry

• Sardines

• Other appropriately selected seafood

• Organ meats can contain substantial iron, although liver requires special consideration during pregnancy because of its high preformed vitamin A content

Heme iron from animal foods is generally absorbed more efficiently than nonheme iron.

Nonheme iron sources

• Lentils

• Beans

• Chickpeas

• Pumpkin seeds

• Dark leafy greens

• Quinoa

• Iron fortified foods

Plant based iron can absolutely contribute to iron intake, but absorption is generally lower.

One simple way to improve absorption is to pair iron rich foods with vitamin C.

For example:

• Beef with bell peppers

• Eggs with berries or citrus

• Lentils with tomatoes

• Beans with salsa and peppers

• Leafy greens with strawberries or lemon

• Meat with broccoli or Brussels sprouts

Vitamin C improves absorption of nonheme iron.

Pay Attention to What You Take With Your Iron

Sometimes the issue isn't simply how much iron someone consumes. It is how well they absorb it.

Coffee and tea contain compounds that can interfere with iron absorption. Large amounts of calcium taken at the same time can also reduce absorption.

If you are actively trying to improve iron status, consider separating iron rich meals or iron supplements from:

• Coffee

• Black or green tea

• Calcium supplements

• Large amounts of dairy

Another old-fashioned tool worth remembering is cast iron cookware. Cooking certain foods in cast iron can modestly increase their iron content. It isn't a replacement for treatment when someone is deficient, but it can be another small nutritional tool.

What About Iron Supplements?

This is where I strongly prefer lab guided supplementation rather than blindly adding large amounts of iron. Not every pregnant woman needs the same amount or form of supplemental iron.

The World Health Organization recommends daily iron and folic acid during pregnancy as a population level strategy, generally providing 30 to 60 mg of elemental iron daily plus 400 mcg of folate (B9).

When someone is already iron deficient, however, treatment is individualized.

Different forms of iron also have different tolerability. Some women develop significant constipation, nausea or digestive upset from traditional iron preparations. Other forms may be better tolerated. And more is not automatically better.

Iron is one nutrient where supplementation should be purposeful. If levels aren't responding despite supplementation, the answer isn't always simply taking more. It may be appropriate to look at adherence, absorption, inflammation, gastrointestinal issues, ongoing blood loss, B12 and folate status or whether a different treatment approach is needed.

Significant anemia or iron deficiency during pregnancy should be managed with the obstetric team, particularly later in pregnancy when there is less time available to rebuild stores before delivery.

Don't Wait Until the Third Trimester to Think About Iron

Ideally, iron status should be addressed before pregnancy or early in pregnancy, not discovered when delivery is only weeks away. If ferritin is already depleted before conception, pregnancy creates an even greater demand on an already limited reserve. Preconception care is therefore an excellent time to evaluate iron status and investigate why stores are low.

Heavy menstrual bleeding?

Low dietary iron?

Poor absorption?

Digestive dysfunction?

Frequent pregnancies?

Recent pregnancy or breastfeeding?

Inflammation?

Simply replacing iron without considering why it became depleted can mean repeatedly chasing the same problem.

And If You're Not Pregnant?

This still applies to you. You do not need to be pregnant to have depleted iron stores.

Women with heavy menstrual cycles, restrictive diets, digestive problems, frequent blood donation or other sources of blood loss may gradually become iron deficient. Women of reproductive age are particularly vulnerable to iron deficiency.

Fatigue, exercise intolerance, feeling cold, headaches, dizziness, shortness of breath, restless legs or hair shedding can sometimes accompany iron deficiency, although none of these symptoms proves that iron is the cause.

Instead of guessing, test first.

At Legacy Wellness, we can review your bloodwork from a functional perspective, look at the pattern across your iron markers and help determine whether nutritional strategies or supplementation may be appropriate based on your individual results.

Because whether you're preparing for pregnancy, currently growing a baby or simply trying to feel your best, the goal shouldn't be to wait until your body is completely depleted before paying attention.

Build the reserve before you need the reserve.

To order labs and learn more about your health, click HERE to order. Lisa Metzger, ND, FBCA

Legacy Wellness

This content is for educational purposes only and is not intended to diagnose, treat, or replace individualized medical advice. Iron deficiency and anemia in pregnancy should be evaluated and managed in collaboration with your healthcare provider or obstetric care team. Always consult a qualified practitioner before starting or changing supplements, especially during pregnancy.