Dr. Paul Van Buynder, the deputy chief medical officer of health, said the public health office was incredibly pleased with the response from pregnant women during the H1N1 vaccination campaign last fall.
Van Buynder said more than 80 per cent of pregnant women received their H1N1 vaccine, but the same group of women did not take the risks of seasonal flu as seriously.
Typically, less than 20 per cent of pregnant women get that vaccine.
"It is very low and we're very disappointed about it," Van Buynder said.
"We're trying to find out why pregnant women in huge numbers had the pandemic influenza vaccine but don't get the seasonal vaccine."