Oh, the scourge of gestational diabetes. Doesn’t pregnancy inflict enough hardships on a woman’s body, with its aches, swelling, nausea, cravings, heartburn and sleepless nights? Must it also alter blood sugar and deny an expectant momma the solace of sweets and carbs to get her through those trying nine months?

A recent study published in the journal Diabetologia describes a newly discovered link between high iron levels during pregnancy and gestational diabetes. Through a series of blood tests conducted on 321 pregnant women, the researchers found those with the highest iron levels had a significantly increased risk of gestational diabetes. This was true in both the first and second trimesters.

Gestational diabetes results partly from the way pregnancy hormones affect the body. They make it tougher for the body to use insulin, which raises blood sugar levels and triggers the need for even more insulin than normal. How might iron play into all this? The relationship between elevated iron levels and this condition hasn’t been clearly defined, but the study’s authors suggest high iron levels may overstress certain cells.

They also cite other studies that show a link between excess iron and diabetes in people and animals who aren’t pregnant. Specifically, damaged pancreas cells can cause a drop in insulin production. This means the body falls further behind in its ability to control blood sugar. Diabetes can result.

The researchers also question the current recommendation for all pregnant women to take iron supplements, suggesting instead that only expectant mothers lacking iron should take them.