I have 3 bitches one of which is in pup.Unfortunately I have just found several fleas on them even though they were all frontlined about 10 weeks ago(spot on).
I will re-treat  the other 2 but  don't want to do the pregnant one for obvious reasons.
I've read several posts here about giving a garlic capsule daily but what happens when the pups arrive.Does the garlic come through in the milk???
What's the safest to use in pregnant and lactating bitches??

I use Stronghold, dead easy, and the puppies do not have worms either! I start worming the pups when they get to 5 weeks, (never seen a worm!) and they have stronghold just before they go to their new homes to cover them for the first month.

I started to use it when we had trouble with fox mange, but it prevents ticks as well which is a real bonus here too.

I am sure I saw a comb recently (possibly for cats, but can't remember where) that emits an electrical pulse that kills fleas when being used - if this was not my imagination would this be suitable?

They used to sell those combs in argos, not sure if they still do - so no you werent imagining it ;)