This is someting, as you realise, that is So personal.
When I was Pregnant I only had one or two horses. The rideable ones went on loan to a friend who ran a riding club once I had the baby in tow. I rode for quite a while while pregnant, but then Fattyhorsepig is/was a very, very reliable, trusworthy horse. Once I had the sprog to look to I put the nags on hold for a while, ...mind you I didn't have such a good time actually giving birth....won't go into details
........The super himan in me was at a very low ebb.
You may find that you become a different person once you are pregnant or given birth, you may not feel different, but I bet your thought processes will change and you'll re-organise your priorities, this is something you cannot and must not plan for as you cannot predict the way your hormones will re-arrange your brain....and they will!
Yes, you can do both, but only those of us fortunate to have nannies and grooms can do it with any real success. I had neither, so something had to go on hold, just for 12 months, then it was full steam ahead.
If you are lucky and have a load of doting freinds just waiting to baby sit tiny baby then you will be fine. I had no body to help at all. If I got 20 minutes a week of someone else baby sitting that's all I had, it was Mega, mega hard work.
Take things one day at a time, there is never a right time to have a baby, you can put it off for years and years waiting for the "right" time....it never does come if you're not careful.
See which way your mind is going to go. I'm certainly not the same person as I was before I had kids, I'm still a bit of a hooligan, but not half as dangerous as I used to be, once you have experienced the "mother tiger" in you, it may just shock you at the depth of feelings and emotion you are capable of.
I consider myself not a brave rider, I don't do X country any more or jump anything bigger than about 3 feet high.....I think I am now a whimp......there are folk out there who still think I'm off my head and will ride nutters!....I pick my nutters very, very carefully these days!
By the way, once young'un is here I bet you won't be able to bring yourself to ride while he/she is napping....you'll want to nap too!