By Stephanie Stahl

PHILADELPHIA (CBS) —  It’s called gestational diabetes, a condition that 9% of pregnant women will develop.

New research finds that women who eat a lot of potatoes before they get pregnant, have an increased risk.

READ MORE: Ready To Restart The Race: Phil Keoghan Talks About The Return Of "The Amazing Race' After A 19-Month "Pit Stop"

Laurie Finberg never thought twice about eating a baked potato, even before she was expecting.

“I had a pretty balanced healthy diet, before I was pregnant,” Laurie said. “Yeah, potatoes are part of my diet.”

A new study from the National Institues of Health found eating potatoes before conceiving may be linked to gestational diabetes.

“Potatoes elevate blood sugar in people more than just about any other food,” said Dr. Aldo Palmieri, a researcher. “They are carbohydrates and all carbohydrates have that potential.”

READ MORE: Philadelphia Veteran Marching To Gov. Wolf's Home To Urge Action On Gun Violence

Researchers asked more than 15,000 women how often they ate potatoes over a 10 year period and tracked their pregnancies. Women who ate more potatoes had higher rates of gestational diabetes than those who consumed fewer potatoes.

“This is a study that reinforces the idea that we should eat in moderation,” Dr. Palmieri said.

Researchers found substituting other vegetables, legumes, and whole grain foods for two servings of potatoes a week lowered the risk of gestational diabetes, by nine to 12 percent.

Obesity is one of the main risk factors for diabetes during pregnancy, but the study did not find that potatoes directly cause gestational diabetes.

Experts say the issue with potatoes isn’t so much the calories.

MORE NEWS: Penn To Initiate Process To Review Complaints After Professor Amy Wax's Anti-Asian Comments

They also have a big impact on blood sugar and glycemic index, which is linked to weight gain and diabetes.

Stephanie Stahl