But some children born to those women may have already been affected.
The change in advice, say territorial health officials, is the result of the discovery of an error in a recent PCBs study of 240 Mackenzie and Kitikmeot area women in their child-bearing years.
Researchers originally told the women that none had levels of PCBs in their blood above the "level of concern" set by Health Canada of 58 parts per billion (ppb).
But in September, scientists preparing a similar study for the Baffin discovered a wrong unit of measurement had been used by territorial researchers. The actual level of concern is five ppb.
After confirming the error, scientists told participants that many of them -- 40 per cent of the Kitikmeot women -- have levels several times the level of concern.
One had a PCB reading of 26 ppb -- more than five times the concern limit.
The affected women were all contacted and given personal briefings on the situation.
Scientists used to consider PCBs, a group of chemicals now banned but once used in electrical equipment, a cancer risk. Some now suspect they pose a more serious threat to the development of children in the womb.
Among the suspected effects are lower IQs and birth weight and behavioral problems.
PCBs are found in many marine mammals, particularly the fat, or blubber. But there has been little research on their effects on humans.
Jay Van Oostdam, the scientist who confirmed the error, said preliminary reports suggest that low levels of PCBs could be dangerous.
"What we have is little bits of information that suggest there is a danger. But in many ways, the effects are still unknown," he said.
"We may be too high or too low at five ppb, we just don't know at this point where the danger really starts."
Van Oostdam added that the effects of PCB contamination on a fetus are similar to those from a mother who smokes or drinks alcohol while pregnant.
"It's very difficult to tell these contaminants apart," he said. "Therefore, it's difficult to tell if PCBs are what's causing the problems."
Despite the uncertainty in the scientific community, Health Minister Kelvin Ng told MLAs last week that "no one is in danger."
He later told News/North that "nothing is proven" and referred questions to NWT medical officer Andre Corriveau.
Corriveau conceded there are troubling questions about PCBs, but said that, given a choice between the known health benefits of traditional foods and an "unquantifiable health hazard," he will choose the former.
"I'm not ready as a medical officer to tell you that you have to cut these kinds of foods from your diet," he said.
Still, women in the Kitikmeot are being advised to replace marine mammal fat in their diet with less-contaminated caribou, fish and other meat.
Studies of the Baffin and Keewatin region are scheduled for 1997. Similar studies in Northern Quebec and Greenland, said Corriveau, have turned up PCB levels even higher than those of the Kitikmeot.