Shalom, A first child/son was born to a couple (she’s a BT, he’s an FFB). without consulting a rav, they decided to do a pidyon haben, though she had an abortion prior to their marriage. They’re raising this child to believe that he’s a bechor. Is there a hallachah issue with him being raised as a bechor? What’s the situation with doing a pidyon haben when one doesn’t hallachakly have to? I don’t understand why people do "this" when they can just avoid an ’embarrassment’ by saying they had a miscarriage!? - This child was born 12 months after they married. Also, does one do a pidyon haben even if there’s a miscarriage? If yes, up to what number of weeks of pregnancy? (I know someone that, too, did a pidyon haben after experiencing a miscarriage very early on in her pregnancy) TIA

I'm sorry I didn't not fully understand your question if the woman in question had an abortion of a developed child or a miscarriage. Although, most of us grew up understanding that a pidyon Haben is only for the absolute 'Peter Rechem" that which initiates the womb, and any child born afterwards is no longer a firstborn that is not fully accurate. The Shulchan Aruch does discuss a case in which a woman miscarried a fetus in which no limbs or organs were developed and the child afterwards is a Bechor and does a pidyon. (See Rema Shulchan Aruch 305:23).In each case a competent Rabbi should be consulted. If the woman had an actual birth of actual child, it changes the picture totally to a discussion not meant for the scope of this site. All the best.