The Best Iron Supplement During Pregnancy

Pregnancy is a special time that requires careful nutritional support to ensure the health of both the mother and the developing fetus.

But some 50% of pregnant women, even in developed countries such as the UK, are thought to be iron deficient. (1)

Studies show that iron deficiency anemia in pregnancy is linked to increased health risks for the mother, including respiratory issues, fatigue, and infections, and can lead to poor outcomes for the baby such as growth retardation, low birth weight, and cognitive and delays.

Unfortunately, however, almost all iron supplements come with unpleasant side-effects, making the process of balancing iron levels fraught with difficulty.

This article aims to provide a comprehensive analysis on the various iron supplements you might choose. 

Best Iron Supplement for Pregnancy

How Much Iron Does a Pregnant Woman Need?

The recommended daily allowance (RDA) of iron for pregnant women is 30 milligrams. This is nearly twice the amount of iron that nonpregnant women need.  

During pregnancy, a woman's blood volume increases by about 50%, and she needs extra iron to produce more red blood cells to carry this extra blood. Iron is also important for the development of the fetus and placenta.

Most women can get enough iron from their diet, but some pregnant women may need to take an iron supplement. This is especially true for women who are carrying twins or triplets, have low iron levels at the start of pregnancy, or have difficulty absorbing iron from food.

Why Iron is not Given in First Trimester?

There are two main reasons why iron is not typically given in the first trimester of pregnancy:

  1. Some studies indicate Iron can worsen nausea and vomiting. This is because most types of iron can irritate the stomach lining. Morning sickness is already a common problem in the first trimester, so taking iron supplements can make it worse.
  2. There is some concern that iron could be teratogenic. Teratogenic means that it can cause birth defects. This is because iron is a powerful oxidant, and it can generate free radicals, which can damage cells.

When Should a Pregnant Woman Start Taking Iron?

Pregnant women should generally start taking iron supplements at the beginning of the second trimester, around week 13. However, the timing may vary based on individual iron levels and overall health.

Healthcare providers typically check iron status during the first prenatal visit and continue monitoring it throughout pregnancy. Women with normal iron levels and a low risk of anemia may be advised to get their iron from a balanced diet during the first trimester. However, women with iron deficiency anemia or a high risk of anemia may be recommended to start iron supplements earlier.

Comparing the Best Types of Iron Supplement During Pregnancy

The simple fact is that the majority of the iron supplement market is made up of products containing forms of iron like ferrous sulfate. These are cheap to produce but cause a variety of side-effects, some of which can be very serious.

More specialist bands choose more refined or specfic forms of iron based on absorption efficiency, and reduced gastrointestinal issues.  

Are Iron Supplements Safe for Pregnancy?

Several studies show that that oral iron had a good safety in patients with anemia during pregnancy. In fact, they are recommended for most pregnant women who have tested as iron deficient.

Iron is essential for the production of red blood cells, which carry oxygen to the baby. During pregnancy, your body's need for iron increases to support the growing baby and placenta.

If you do not get enough iron from your diet, you may develop iron deficiency anemia. This condition can cause a number of problems for you and your baby, including:

  • Fatigue
  • Shortness of breath
  • Dizziness
  • Palpitations
  • Increased risk of postpartum hemorrhage
  • Increased risk of low birth weight and premature birth

The Best Iron Supplement for All Areas of Pregnancy

Best for Preconception and Postpartum

During the preconception and postpartum periods, finding an iron supplement with excellent bioavailability is key. It's important to select a product that allows your body to absorb and utilise the iron efficiently, especially during these times when your iron requirements may be increased.

Additionally, considering an iron supplement that is designed to be gentle on the stomach may make a significant difference. Traditional forms of iron, such as ferrous sulfate, are sometimes associated with side effects like nausea and constipation, which you may wish to avoid.

Lastly, opting for a supplement that is pure and straightforward—free from unnecessary additives, certain vitamins, or fillers—might be beneficial, particularly if you have sensitivities to common ingredients in iron supplements.

It's crucial, however, to consult with a healthcare provider before choosing an iron supplement for preconception and postpartum. They can offer personalised advice, taking into account your specific health needs and nutritional requirements, ensuring the supplement you choose is most appropriate for you.

Best Pregnancy Iron Supplement for Nausea & Indigestion

Traditional iron supplements often lead to gastrointestinal side effects for a couple of key reasons.

Firstly, these supplements typically contain iron in a form that is not readily absorbable, requiring the digestive system to work harder to extract the necessary elemental iron. This process can irritate the lining of the gastrointestinal tract, resulting in symptoms such as nausea and constipation.

Secondly, studies show that the unabsorbed iron enters the colon, where it can disrupt the microbial balance, further exacerbating digestive discomfort.

Best Liquid Iron for Pregnancy

For those who find swallowing pills uncomfortable or have dietary restrictions that make solid supplements less feasible, liquid iron supplements are often the go-to solution. Liquid supplements may also offer faster absorption rates, making them an appealing option for individuals who require immediate iron intake.

This study showed that oral ferrous gluconate in liquid form is more effective and above all better tolerated than other solid or liquid formulations containing elementary iron.

Best High Dose Iron for Pregnancy

For some expectant mothers, the journey through pregnancy comes with added challenges due to existing health conditions like anemia. The body's need to nourish the developing fetus can exacerbate these conditions, making adequate iron intake critical. Additionally, mothers expecting twins or triplets face a similar predicament, as their bodies must work doubly or triply hard to absorb and disperse nutrients effectively to each fetus.

Traditional high-dose iron supplements are often insufficient in these scenarios. Their poor absorption rates mean that much of the iron isn't effectively used by the body. Additionally, side effects such as gastrointestinal issues can make it hard for mothers to stick with a high-dose regimen.

Best Iron Supplement for Pregnancy with Zero Additives or Fillers

Many supplements contain additional nutrients to aid in absorption, fillers for bulk, and sometimes artificial preservatives or colours. While these additives may serve specific functions, they also introduce the possibility of sensitivities or allergic reactions. For those who are vigilant about what they consume, this can be a concern.

Best Gentle Iron Supplement for Pregnancy

Traditional iron supplements, even those marketed as "gentle," frequently contain forms of iron that are not easily absorbed by the body. This often leads to a catch 22 for pregnant women of being unable to optimise their iron levels without unpleasant digestive issues such as constipation or diarrhea.

When Should You Begin Prenatal Iron Supplementation?

The demand for iron increases significantly during pregnancy to support both fetal development and the mother's expanding blood volume. Medical guidelines in the United Kingdom generally recommend starting prenatal iron supplementation in the second trimester.

However, it is important to consult with a healthcare professional for personalized advice, as iron needs can vary depending on factors such as pre-existing iron levels and dietary intake.

How to Choose the Right Iron Supplement During Pregnancy

Choosing an iron supplement during pregnancy is a crucial decision, as iron is essential for the health of both the mother and the developing fetus. When making your selection, it is important to consider the following factors:

  • Bioavailability: This refers to the amount of iron that is absorbed into the bloodstream. 
  • Form of iron: Choose a form of iron that's easier for the body to absorb.
  • Compatibility with other nutrients: Nano Iron is compatible with other nutrients, such as vitamin C, which can help to further enhance iron absorption.
  • Gastrointestinal tolerance: Iron supplements can sometimes cause gastrointestinal side effects, such as constipation and nausea. Nano Iron is often better tolerated than other forms of iron, making it a good choice for pregnant women.

Nutrients That Improve Iron Absorption During Pregnancy

The effectiveness of iron supplementation is not solely dependent on the type or dosage of iron, but also how well the body can absorb it. Several nutrients are known to facilitate the absorption of iron, thus enhancing the overall efficacy of the supplement.

  • Vitamin C: This nutrient forms a complex with iron, increasing its solubility and absorption. Consuming foods rich in Vitamin C like citrus fruits alongside your iron supplement can improve bioavailability.

  • Heme Iron: Found in animal sources, heme iron is generally more easily absorbed than non-heme iron found in plant sources. If your supplement contains heme iron, it may lead to better absorption rates.

  • Copper and Manganese: These trace elements are not as well-studied as Vitamin C, but some evidence suggests they could also aid in iron absorption.

  • Amino Acids: Some amino acids, like lysine, have been found to improve iron absorption, making protein-rich foods a good companion to iron supplements.

Optimal Time of Day for Iron Intake During Pregnancy

The timing of iron supplementation can significantly influence its absorption and efficacy, and several factors come into play when determining the optimal time for intake.

  • Empty Stomach: Taking iron on an empty stomach can improve its absorption; however, this can also lead to gastrointestinal discomfort for some individuals. (Nano Iron on the other hand is designed to be taken on an empty stomach)

  • Meal Timing: If taken with a meal, it's advisable to consume iron-rich foods or those that enhance iron absorption. However, certain foods like dairy, tea, and coffee can inhibit iron absorption and should be avoided.

  • Medication Interactions: If you are taking other medications, particularly antacids or calcium supplements, the timing should be staggered to avoid interference with iron absorption.

  • Consistency: Maintaining a consistent schedule for iron supplementation

Natural Alternatives to Iron Supplements During Pregnancy

There are a number of natural alternatives to iron supplements that you can eat during pregnancy to help meet your iron needs. Some of the best sources of iron include:

  • Red meat: Red meat is the best source of heme iron, which is the type of iron that is most easily absorbed by the body. Good choices include beef, lamb, and pork.
  • Poultry: Poultry is another good source of heme iron. Chicken and turkey are both good choices.
  • Fish: Fish is a good source of both heme iron and non-heme iron. Non-heme iron is not as easily absorbed as heme iron, but it can still be absorbed by the body, especially when eaten with foods that contain vitamin C. Good choices include salmon, tuna, and mackerel.
  • Beans and lentils: Beans and lentils are good sources of non-heme iron. They are also a good source of fiber and other nutrients.
  • Leafy green vegetables: Leafy green vegetables, such as spinach, kale, and collard greens, are good sources of non-heme iron. They are also a good source of vitamin C, which can help the body absorb iron.
  • Dried fruits: Dried fruits, such as apricots, raisins, and prunes, are good sources of non-heme iron. They are also a good source of fiber and other nutrients.

In addition to eating iron-rich foods, you can also help your body absorb iron by eating foods that contain vitamin C. Vitamin C helps the body to convert non-heme iron into a form that is more easily absorbed. Good sources of vitamin C include citrus fruits, berries, tomatoes, and broccoli.

Frequently Asked Questions on Iron Supplementation During Pregnancy

What role does iron play in fetal development during pregnancy?

Iron is crucial for fetal brain development and the formation of healthy red blood cells. It also helps prevent anemia in the mother, which can lead to complications such as preterm birth and low birth weight.

How does the iron requirement change across different trimesters?

Iron requirements generally increase as pregnancy progresses. Iron tablets are generally not prescribed in the first trimester unless the mother has been diagnosed with iron deficiency anemia. However, as you enter the second and third trimesters, the demand for iron increases significantly to support the expanding blood volume and fetal growth.

Is it possible to develop iron-deficiency anemia during pregnancy, and what are the risks?

Yes, it's possible to develop iron-deficiency anemia during pregnancy. Risks associated with this condition can include increased fatigue, low birth weight, preterm delivery, and in severe cases, developmental delays in the child.

Are there specific tests to determine my iron levels during pregnancy?

Common tests for determining iron levels include a complete blood count (CBC) and a serum ferritin test. Your healthcare provider will guide you on when and how often these tests should be conducted.

What are the common side effects of iron supplements during pregnancy?

Common side effects of traditional iron supplements can include gastrointestinal issues such as constipation, nausea, and diarrhea. These effects can sometimes make it difficult to adhere to a supplementation regimen. Most or all may be avoided with Nano Iron.

Can I take iron supplements alongside other prenatal vitamins and minerals?

Yes, iron supplements can generally be taken with other prenatal vitamins, but it's important to consult your healthcare provider for specific advice, as some vitamins and minerals can interact with iron absorption.

What is the best time to take iron tablets during pregnancy?

The optimal time to take iron tablets is usually in the second and third trimesters, as iron demands increase. Iron supplements are best absorbed on an empty stomach, but if they cause stomach upset, they can be taken with a small amount of food. Avoid taking them with calcium-rich foods or drinks, as calcium can interfere with iron absorption.

What is the best iron supplement for pregnancy in the third trimester?

A bioavailable iron is ideal in the third trimester when the demand for iron peaks due to rapid fetal growth and the need to build maternal and fetal iron stores for delivery and lactation.

What is the iron supplement dosage for pregnancy?

The typical dosage for an iron supplement during pregnancy is 30 to 60 mg of elemental iron per day, as recommended by healthcare providers based on individual needs.

When should I stop taking iron tablets in pregnancy?

Iron supplements are usually continued until the hemoglobin and ferritin levels return to normal. Some healthcare providers recommend continuing iron supplements until the postpartum checkup, while others may advise continuing them for several weeks postpartum, especially if the mother experienced significant blood loss during delivery. Always follow the guidance of your healthcare provider.


(1) Abu-Ouf, N. M., & Jan, M. M. (2015). The impact of maternal iron deficiency and iron deficiency anemia on child’s health. Saudi Medical Journal, 36(2), 146-149.

(2) Weinberg ED. Can iron be teratogenic? Biometals. 2010 Apr;23(2):181-4. doi: 10.1007/s10534-009-9285-5. Epub 2009 Dec 19. PMID: 20024603.