my nanna had 4 kids and went to the docs with a "virus" she couldn't shake, dr said start knitting you are 5mths preg - she had her period all the way through and after having 4 children you would think that she might have known she was pregnant. now all this was going back some 40 yrs ago and i don't know any other details, but she died around 7yrs ago, so i only really know what my mum and aunties have told me.