Increased risk of SPD, a risk of things getting looser, your bump may look larger than necessary towards the end as your belly over stretches, can take a wee while longer for things to 'snap back' after birth (or never), more stretch marks, if you are clumsy now, it will be 10 xs worse during pregnancy lol.
Birth shouldn't be an issue except for some of us are more likely to have earlier births, faster births, excessive bleeding, tissue damage.
That said, out of all my three, first was induced on time (but they claim two weeks late) and from start to finish was 12/13 hours, second was 3 weeks late and took 12 hours and 3rd was on time and 6 hours in length max. First was in hospital, other 2 were born at home. I didn't know I had hms/eds with the first 2 but the Ob cleared for home birth with my 3rd, he couldn't see why not even with hms/eds (but he is a very good Ob who is woman centered rather than hospital policy centered, my GP made sure I got him). I had second degree tears with all but they healed well and not much bother except for number one which was a botch repair job.
Post Partum, I always get worse. My pain was easy to manage pre children with just paracetamol and ibuprofen, now I use paracetamol, ibuprofen, tramadol and buprenorphine patches and I am still in pain (although I can breastfeed with the meds). I am really glad I had kids though, the fun etc I have with them is worth all the pain in the world.
I think the most important thing you can do to prepare for pregnancy is excercise, I didn't with my first two and really suffered, this last time, I exercised, despite awful spd (in fact, using a stepper was the only thing that relieved it because it manipulated things back into place). I gained 4 stone in my last pregnancy and now, 5 months later, I have lost over 3 stone of it and feel much better and healthier because of the exercise.