Congratulations!
I really think that apart from asking about extra fetal testing, you can crack on with processing this momentous news, and getting the practical things ready.
I was born in 1971, in an upper middle class community. Many of the mums smoked and drank during pregnancy- even those non-addicted. In fact my mum tells me some women took up or increased smoking, to try and reduce the birthweight of the babies (presumably makes for an easier labor). I know, pretty shocking! But my point is this was normal.
If I think of my primary school, there was no more incidence of disability then, following these pregnancies. Families we knew didn’t have more kids born with problems. I suspect there might have been more early miscarriages, but no late-term ones (I’d remember).
We are right to worry about drinking and smoking in pregnancy, now that we know. It seems obvious to (most of) us to not do it (not even once) but don’t forget that we’re only the 2nd generation in human history to think this way. And public health campaigns have to use scare tactics in order to cut through the cultural noise and get heard.
I’m also tempted to say that looking backwards and hand-wringing won’t change anything. It’s normal to feel this way- a potent mixture of fear, shame, guilt and shock. But in order to give this wonderful little human a great life, start looking forwards. Once they’re born, kids mostly prevent you looking back or ahead, they certainly focus you on ‘living in the moment’!