Antibiotics during labour

I am currently 20w1d pg and i have to have antibiotics during labour. I have a heart condition so there is no question about it. With my last 2 pgs i just stayed on the bed but with this one i am thinking of getting up and moving. With DS (the most recent) i was induced, and in that much pain i couldnt have pain releif, little own get off the bed. So here's what im thinking,
A)NOT getting induced unless neccisary
B) Walking most of the first stage of labour.
But is it possible to not have the antibiotics until later on in labour (ie just before i go into 2nd stage or im 7-10cms dialated).?:confused:
I will be discussing this with my hospital @ 30weeks but i dont see them until then because i am doing shared care with my doc.
Sorry for all the questions,

I have a heart murmur and I had to start taking antibiotics at the onset of labour, but I couldn't justify paying $30 for them if I didn't know when labour was going to start IYKWIM? So I didn't take them because I also knew that they would give me an antibiotics injection there anyway. As soon as I got to hospital, they gave the the injection and I still had an active labour despite ending up having a syncto induction due to Paige passing mecconium.

With the antibiotics, you will still have to take the full course anyway - I had the injection first which was a big dose and then for the next 5 days I just took them as you normally would. it is hard to say if you can put them off, because you don't know how your labour is going to progress - you could go really quick and not have time KWIM. It was easier for me to have it straight up and then I didn't have to worry about it later.