One of the great joys of pregnancy is that no one looks at you twice when you ask for another serving. Now research shows that especially applies to the bread basket on the dinner table.

According to a study published last week in the journal Birth Defects Research, expectant mothers who restricted their carbohydrate intake were 30% more likely to have a child with a neural tube defect, such as spina bifida.

For the study, researchers from the University of North Carolina at Chapel Hill analyzed data from the National Birth Defects Prevention Study, which included information on 1,740 cases of anencephaly or spina bifida as well as 9,545 cases without birth defects. They found that women who restricted their carbohydrate intake before pregnancy and during pregnancy had significantly lower levels of folic acid—which is essential to the healthy of developing fetuses.

These findings should send a clear message that women who hope to become pregnant should loop their health care providers in as soon as possible, says lead researcher Tania Desrosiers, PhD, MPH, and research assistant professor of epidemiology at the UNC Gillings School of Global Public Health.

“This is concerning because low carbohydrate diets are fairly popular,” Desrosiers says in a press release. “This finding reinforces the importance for women who may become pregnant to talk to their health care provider about any special diets or eating behaviors they routinely practice.”

According to the 2017 Prenatal Health & Nutrition survey, only 34% of women take prenatal vitamins before learning they are pregnant. However, neural tube defects (NTDs) occur within the first month of pregnancy—often before women are aware they are expecting.

Because of this gap, the March of Dimes reports seven in 10 cases of NTDs could be prevented if women of childbearing age took multivitamins with at least 400 micrograms of folic acid every day.

As the latest research suggests, another possible solution for those who struggle to remember to take daily vitamins is just to load up on folic acid-rich or enriched foods, such as fortified pasta and bread or the gluten-free options of leafy greens, beans and citrus fruits.