The other thing to keep in mind is that a cheeseburger, in particular, may also be slightly riskier than other foods, because undercooked beef can contain E.Coli, according to the FDA . When you're pregnant, your immune system is compromised, so it's harder to fight off food-borne illnesses like this. We can assume that In-N-Out follows the proper food safety protocols that would prevent this from happening, but that possibility may be why her doctor also tried to dissuade her from eating cheeseburgers. (We reached out to In-N-Out for comment, but didn't hear back at the time of publication)