Pregnant women who are looking for an excuse for their forgetful nature can no longer blame "mommy brain" or "pregnancy brain" as the cause.

Why?

Because "it's all in their heads," according to a new study from Brigham Young University.

Mommy brain is defined as the state in which new mothers are forgetful, absentminded or easily distracted.

A team of neuroscientists from the university observed 21 expectant mothers by testing their memory skills. Participants were asked to recall specific items, such as shopping lists and stories, or they were asked to remember certain visual and spatial locations, Fox 13 reported.

"There's been a conception for a long time that women don't have as good of memory, particularly after they get pregnant and have a child," study leader Michael Larson, who is an associate professor of psychology and neuroscience at BYU, said about the stereotype.

The women took a three-hour test in their third trimesters, and then they were reevaluated three to six months after giving birth.

"We went in without a clear knowledge of what was going to happen," Larson said. "Some studies say, yes there are memory problems, some studies say, no. Our study suggests that on the lab measures, there weren't objective memory impairments. But in the self-report, the women definitely felt like they were having a hard time."

Researchers compared their results with another group of 21 women who were not pregnant and had no children, and found that expectant mothers and post-partum women had no significant cognitive differences.

Hence, mommy brain is now considered to be a myth.

Larson said, however, that pregnant women may feel as if they are suffering from "mommy brain" due to increased stress levels and having a more demanding lifestyle. Fatigue can also be a factor.

"I think it's this perception between the lack of sleep, the feeling of discomfort, and the overall decrease in quality of life that people just don't feel as good, so they start to think, hey there's a correlation here with pregnancy," he said.

None of the women who participated in the study had depression or postpartum depression, but Larson explained that he thinks women who are depressed to begin with may be more likely to experience so-called symptoms of mommy brain.

Whether a myth or not, when pregnant women were asked to rate their quality of life, they provided lower scores than their non-pregnant peers, according to Deseret News.

"Pregnancy brain isn't a myth," said Alexis Torres, who is seven months pregnant with her first child. "It doesn't matter what the doctors say - when you're pregnant, you forget things."

The findings were published online in the Journal of Clinical and Experimental Neuropsychology.