Hi there. Yes, that is not an accurate way to check for pregnancy. The only way to know you are pregnant is to use something that will be sensitive to the hormones specifically from a pregnancy. Baking soda is not able to do that.
Baking soda will foam with anything acidic. Urine is acidic hon. good luck
I heard that was for a gender test not to see if you're actually pregnant, but either way those kind of things are not usually accurate