Hiya, thought I'd add my two pennies.
Started my pregnancy with a BMI of 35 which put me in the obese category, midwife recommended 5mg folic acid and 75mg aspirin due to my weight and the increased risk of neural tube abnormalities and blood clots.
I'm not sure if it's recommended to have the increased folic acid dose whilst TTC, might be worth your looking into, maybe speak to your GP what with neural tube abnormalities developing in the first few weeks of pregnancy and you might not know your pregnant by then.
Pregnancy wise I've chosen to try and not gain too much weight, I'm currently 37+4 and have gained 17lbs, my midwife recommended a max weight gain of 20lbs so I'm happy with that. I've been low carving pre pregnancy as a way of losing weight (lost 4stone) so have maintained that to a certain extent but if I've wanted pizza I've had pizza.
I've not taken up any additional exercise, I know me and I know I wouldn't keep it up! I have a moderately active job and that's good enough for me. I'm glad I didn't gain too much weight as I have developed PGP and any more additional weight would have really exacerbated it and made the pain worse.
My midwife recommended aquanatal glasses and yoga and Pilates, they're good for gentle exercise but also for increasing core strength.
The midwife offered to refer me to the healthy living midwife, which I declined, I'm a HCP and know how to eat right (I just don't!) and as I was on the cusp of midwife led care/consultant led care the midwifes wrote to the consultant to say they would like to keep me on their books.
They were pretty honest from the start that my weight may well rule out a water birth, essentially if something happens in the pool they wouldn't be able to be dragging my fat arse out of it, which is fine by me, a water birth wasn't something I wanted.
IVe had additional growth scans due to my weight, three of them, in the later stages of pregnancy to ensure that baby was growing safely and that the placenta and cord flow was fine and I've also had a glucose tolerance test to rule out diabetes. I've actually had the test twice now as my growth scans have picked up that baby is enormous but both my tests have been well within normal parameters and my massive baby is just down to genes on both sides of the families. Lucky me and my pelvic floor 😂
I can honestly say that not one midwife or doctor has made me feel bad about my weight but they obviously had to make me aware of the additional risks of my weight and the pregnancy. They didn't even weigh me from my booking in appointment until my 36 week appointment.
Good luck x