Hi, I understand your concern. Nor walk virus mostly causes spread of infection in society( a sort of epidemic). It s diagnosis is done by history of consumption of polluted food, symptoms of gastroenteritis, absence of any bacteria, amoebae, parasytes in stools. Other blood tests like antigen tests are usually not needed.. as the infection is controlled in 1-3 days. The virus is not known to cause any bad side3 effects on baby.Still it s contact must be prevented .. as dehydration& resulting electrolyte imbalance & possibility of urinary tract infection are the concerning side effects.. which may create problem in pregnancy. Thanks.