Why Maltofer and Ferro-grad C Iron Are Less Effective and Cause More Gastric Upset-Especially in Pregnancy

Iron deficiency during pregnancy is common and requires effective supplementation. However, many women experience poor results or uncomfortable side effects with standard options like Maltofer (iron polymaltose) and Ferro-grad C (ferrous sulfate with vitamin C). Here’s why these products often fall short, and how practitioner-recommended alternatives can offer better absorption and comfort-especially for pregnant women.

Bioavailability Challenges

Maltofer contains ferric iron (Fe³+), which must be converted in the body to ferrous iron (Fe²+) before it can be absorbed. This conversion is inefficient, making Maltofer less reliable for raising iron levels. While it’s marketed as gentler on the stomach, its absorption is slower and less predictable compared to other forms.

Ferro-grad C uses ferrous sulfate, which is better absorbed than ferric iron, but its modified-release design can actually slow down absorption. Even with added vitamin C, the body may not utilize the iron as efficiently as intended.

Both supplements are often prescribed at high doses, which can trigger a hormone called hepcidin. Hepcidin blocks further iron absorption in the gut, so taking large amounts of iron can paradoxically make deficiency worse over time. Practitioner brands often recommend lower, more frequent doses or alternate-day dosing to avoid this problem.

Gastrointestinal Side Effects

Despite claims of being gentle, both Maltofer and Ferro-grad C are well-known for causing gastrointestinal issues. Maltofer may cause less irritation than ferrous sulfate in some studies, but many users still report constipation and nausea. Ferro-grad C, even with its slow-release design, is notorious for causing nausea, constipation, and stomach pain. The form of iron in these supplements can also create oxidative stress, further aggravating the gut.

Practitioner brands often use forms like iron bisglycinate (chelated iron) or liposomal iron. These are much less likely to cause stomach upset because they bypass the harsh effects of ionic iron in the gut.

Pregnancy-Specific Considerations

During pregnancy, iron requirements increase dramatically. Unfortunately, traditional supplements like Maltofer and Ferro-grad C often don’t meet these needs effectively. High-dose iron can increase hepcidin, reducing the body’s ability to absorb iron just when it’s needed most. Pregnancy also heightens sensitivity to GI side effects, making compliance with these supplements difficult.

Many prenatal vitamins contain calcium, which can further inhibit iron absorption if taken together. Practitioner alternatives address these issues by using lower elemental iron doses with added vitamin C for better absorption, and by recommending gentle forms like iron bisglycinate that are easier on the digestive system. Timing strategies, such as taking iron at night or with vitamin C-rich foods, can also improve both absorption and tolerability.

Superior Alternatives for Pregnancy

Iron bisglycinate is chelated to amino acids, which reduces oxidative stress and GI irritation. It’s absorbed two to four times better than ferrous sulfate, even when taken with food.

Liposomal iron is encapsulated in phospholipids, allowing it to be absorbed directly in the intestines and avoiding many dietary interactions that can block absorption.

Heme iron polypeptide, derived from animal hemoglobin, uses a different absorption pathway and can be especially effective, even for those following plant-based diets when combined with vitamin C.

Key Takeaways

While Maltofer and Ferro-grad C are widely prescribed, their forms of iron and dosing strategies often lead to poor absorption and uncomfortable side effects-especially during pregnancy. Practitioner brands offer gentler, more effective options that are better absorbed and easier on the stomach, making it easier for pregnant women to correct iron deficiency and support healthy fetal development. If you’re struggling with traditional iron supplements, consider speaking to your healthcare provider about these more advanced alternatives.