Children of moms who ate a lot of peanuts while pregnant may be at an increased risk of developing an allergy to the nut, suggests a new study.

However, the researchers stop short of recommending that pregnant women avoid peanuts; it is not yet clear if a mom’s consumption can actually cause the serious and potentially fatal allergy that appears to be on the rise - currently affecting about 1 percent of kids.

“Studies have fallen on both sides of this,” lead researcher Dr. Scott H. Sicherer of Mount Sinai School of Medicine, in New York City, told Reuters Health in an email. “It is hard to know what is right or if there is any definitive influence.”

In search of a more solid answer, Sicherer and his colleagues from five other locations across the country studied more than 500 infants between 3 and 15 months old who likely had a milk or egg allergy but no known peanut allergy. Most had not yet tried to eat peanut.

The researchers found that more than a quarter displayed a strong reaction in a peanut “sensitivity” test, with children of mothers who had consumed peanuts during pregnancy at nearly three times the odds of showing this potential indication of the allergy, compared to kids whose mothers had avoided peanuts.

Further, the more peanuts that a woman reported eating while pregnant, the greater her infant’s risk of a positive test, Sicherer and his colleagues report in the Journal of Allergy and Clinical Immunology. Consuming peanuts while breast-feeding, however, did not appear to significantly affect the test result.

The researchers caution that their results fall short of pinpointing a cause and effect relationship. They also note that the children in the study only underwent blood tests for peanut sensitivity, which isn’t the same as a peanut allergy diagnosis.

“We have to wait a few more years to get that extra information,” Sicherer said.

His team is continuing to follow the children to determine what allergies might come and go over time, as part of an ongoing study through the National Institutes of Health’s Consortium of Food Allergy Research.

The new study comes after a flip-flop of recommendations over the last decade concerning maternal peanut consumption. After eight years of advising women to consider avoiding peanuts during pregnancy and breast-feeding if one of the parents or a sibling had allergies, the American Academy of Pediatrics withdrew the recommendation in 2008 due to a shortage of evidence.

The lack of clarity on the issue has left many women confused. “I have had mothers say they ate a lot of peanut and think they caused a peanut allergy, and I have had other mothers say they avoided and wonder why their child has an allergy,” said Sicherer.

“I think that we unfortunately have to say that we do not yet know a certain answer,” he added. “The good part of that conclusion is that mothers should not have a guilty feeling about their past diet decisions.”

SOURCE:  Journal of Allergy and Clinical Immunology, online October 29, 2010.