However, there’s no evidence that bleach reacts to urine with hCG differently than any other kind of urine. And in fact, inhaling bleach fumes can be harmful , so bleach shouldn’t be played with. If you want to take a pregnancy test, it'll both be safer and more accurate to purchase an over-the-counter test — these often cost less than £10 and are available at most pharmacies, as well as online. A blood test, which is done at a doctor’s office and measures the levels of hCG in your blood, is also an accurate way to tell if you’re pregnant.