As I understand it, women who have had miscarriages are sometimes likely to refuse to countenance the idea that they might be pregnant again. They may choose to not even do a pregnancy test, as they don't care to acknowledge a possibility that the whole nightmare could recur. A subconscious refusal to "go through all that again". (Of course it is possible this woman is simply thick as pigshit, I'm just not able to condemn her out of hand.)