Hi HJ
dont think they give a false postitive but they do delay AF, if prog maintainance is a problem for you in pregnancy then they can amke all the difference, they keep the endometrium nice and rich until the placenta takes over, so if youve found in the past when you have you bloods and your prog has dropped off they may just be what you need. Good luck
Oh also i didnt find i needed a pad, i just had one at night but beware as i found i had an orangy colour when i wiped IYKWIM can be abit scary if your not expecting it.