They can also give you oral antibiotics if you refuse the drip. However you would need to be on the tablets for longer prior to birth and this is the reason you are not usually offered the tablets.
Should your baby catch GBS (not common) your baby cab become quite sick. But if your baby’s temp is watched closely for the first 48 hours after birth any rise in the temp could indicate an infection. In this case your baby would need antibiotics which would prevent your baby becoming very sick.
There is currently a new test GBS being evaluated. It is done when you are in labour and the results are ready in just a few minutes. This prevents the problem caused by being negative for GBS but having the bug at the time of birth and vice versa.