Stitch, I have had grade 4 placenta praevia twice.
With DD1 I knew 3 people who had PP but no problems, went to 38 weeks for a planned CS. I assumed I would be the same. How wrong I was! I was admitted at 33.5 weeks after a big bleed that went (sorry, may be TMI) plop into the toilet. I was released after 2 days, only to be re-admitted within 24 hours. I stayed until a planned section at 37.5 weeks. She weighed in at a hefty 8lb 11oz!
With DD2 I asked at my 12 week scan if they could see the placenta, we then guessed it was another PP.
This was confirmed at 21 weeks. I was on a sex ban! No flying, no lifting, no pushing a shopping trolley.........
I was admitted at 24 weeks, 26 weeks, three times at 31 weeks, then at 33 weeks I was in for the duration.
I had been told I could only work part time after the admission at 26 weeks, my boss was fine with this.
At 36 weeks, I had a big bleed that didn't stop, I ended up with an emcs at 36+1. DD2 was 5lb 13oz, no need for special care.
I'm happy to answer any questions about my experiences. There is also another MN called Tinkerbelle who also had PP. I'm sure she'll show up too.