They don't test for it routinely, I happened to have a swab a couple of weeks ago due to either suspected mucus plug or meconium that I'd lost ( it was mucus plug sorry tmi) and it was sent to the lab and they tested it for all sorts of infections and came back with just group strep b and they sent me a letter to let mr know. I think it's a drip they give you during labour from what I've read. It did worry me too but the baby centre had a detailed article that said its very rare for it to affect baby but they give you antibiotic aa a precautionary. I also had a reasonably quick labour last time at 15 hours but I wasn't sure if I was in definite labour until 6 hours before he was born, I was never swabbed during my last pregnancy so not sure if I had it then as ive read lots of ladies carry it without knowing as it is symptomless and doesn't affect our health so I could have had it last time and my little boy was fine, I think of They're concerned about baby they give them anti biotics too. It's definitely nothing to worry about though chick as you'll be in safe hands xxx