She didn’t come back to Seattle alone she had Jr with her and they remained in Seattle. We do have the testimony of a woman who babysat Jr while Ann was living in the apartment on Capitol Hill. Here is a link to the article which appeared in an interior Alaska paper and was reproduced in this blog:
http://redoubtreporter.blogspot.com/2009/01/obama-baby-sitter-awaits-new-era.html
Health care in Canada began with the institution of the government paying 50% of costs in 1946 in the province of Saskatchewan brought into effect by Tommy Douglas(grandfather of Keifer Sutherland). By 1950 Alberta had also instituted a health program similar to that in Saskatchewan. By 1957 the federal government introduced a bill providing for 50% of costs in all provinces and by 1961 all provinces had enrolled in the program.
Because she was married to a British citizen, it would be very easy for her to go to any Canadian hospital at that time. There are towns like White rock that are very close to the border.