<qa>  How many pregnant women followed through pregnancy during the second and third wave of the 2009 influenza pande800 pregnant women followed through pregnancy during second and third waves of the 2009 influenza pandemic, and 200910 influenza season. Forty percent are high risk pregnancies: either for maternal influenza complications eg. underlying asthma, gestational diabetes mellitus in prior pregnancies or high risk for obstetrical complications eg. prior premature birth, multiple pregnancies. Recruitment from Halifax, Quebec City, Toronto, Hamilton, Calgary, Edmonton, and Vancouver. Plan to enroll all women before the beginning of the second wave; however, enrolment of women 20 weeks pregnant will continue at each site until the second wave has peaked locally. 