High Folate Intake in Pregnancy Linked to Gestational Diabetes

Folic acid has long been considered crucial in pregnancy for preventing birth defects. But a new study in Nutrients suggests that when expectant mothers have too much folate in their blood, it may be linked to higher cases of gestational diabetes and shifts in crucial pregnancy hormones. Researchers examined two groups of women in Australia, one before mandatory folic acid fortification in foods and one after, to see how folate levels and pregnancy outcomes had changed over time (1^✔ ✔Trusted Source
Maternal Folate Excess, Placental Hormones, and Gestational Diabetes Mellitus: Findings from Prospective Cohorts Before and After Mandatory Folic Acid Food Fortification

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The Link Between Folate and Gestational Diabetes

After fortification, serum folate increased by 18 percent, and red cell folate surged by 259 percent in pregnant women. Red cell folate (RCF) is considered a more reliable marker of the body’s long-term folate levels, and unlike other measures, it remains stable whether the blood sample is taken in a fasting or non-fasting state.

More than half of the women in the latter group had RCF levels above the clinical reference range. Alongside this, placental hormones that influence blood sugar, such as human placental lactogen and growth hormone variant, were noticeably higher. Most strikingly, women with excessive RCF showed nearly 50 percent more cases of gestational diabetes compared to those whose folate levels were within the healthy range.

How Folate Excess May Influence Pregnancy

Folate is vital for fetal development, particularly in preventing neural tube defects. However, the new findings suggest that when maternal folate levels climb too high, the placenta may begin producing extra hormones that affect the mother’s ability to regulate blood sugar. These hormonal shifts can make her body more resistant to insulin, which in turn raises the risk of developing gestational diabetes mellitus (GDM). While folate deficiency has become rare, excessive folate intake is now emerging as a concern in countries with food fortification policies.

Placental Hormones and Maternal Health

The placenta acts like an endocrine organ, releasing substances that support the growing baby while also adjusting the mother’s metabolism. In women with high folate, researchers observed elevated levels of hormones such as human placental lactogen and prolactin. These hormones can help the body adapt to pregnancy, but when they rise too high, they may interfere with normal glucose balance. This hormone-driven pathway could be one explanation for the link between RCF excess and gestational diabetes.

The Role of Supplements and Fortified Foods

Modern diets often combine fortified foods with high-dose prenatal supplements. Many women also continue taking these supplements well into their second and third trimesters. Together, these practices mean that a large number of expectant mothers are exposed to folate far beyond what was historically recommended. While fortification has been successful in reducing severe birth defects, it has also created a new challenge: widespread folate excess in pregnancy. The study suggests this excess may come with unintended consequences for maternal health.

Personalized Folate Supplementation Plans for Expectant Mothers

These findings do not suggest that folic acid should be abandoned. Instead, they highlight the importance of balance. Preventing birth defects remains a top priority, but health experts may now need to reconsider upper safe limits for folate intake in pregnancy. Personalized supplementation, where a woman’s folate status is checked before adding more, could become a more effective strategy. Countries with mandatory fortification may also need to assess whether additional supplements are always necessary, especially after the first trimester.

Finding the Right Balance of Folic Acid in Pregnancy

The message from this research is not to stop folic acid completely, but to recognize that more is not always better. For mothers-to-be, the healthiest approach may involve a middle ground that ensures adequate folate without tipping into excess. The study opens the door to important discussions about how to protect both mothers and babies in a changing nutritional landscape.

Pregnancy is a time when small choices can have a lasting impact. If you are expecting or planning for a baby, consider speaking with your healthcare provider about your supplement use and diet. Finding the right balance in nutrients today may safeguard both your health and your child’s future well-being.

Reference:

1. Maternal Folate Excess, Placental Hormones, and Gestational Diabetes Mellitus: Findings from Prospective Cohorts Before and After Mandatory Folic Acid Food Fortification - (https://www.mdpi.com/2072-6643/17/17/2863)

Source-Medindia