First I have been a breeder for many years but only have a litter every two to three years so advice etc changes over the years. The subject is worming in pregnancy. Last time my bitch had puppies I tried the worming system which involved worming from day 42. I didn't feel comfortable giving her the wormer everyday and in fact when I did come to worm the puppies at two weeks I found that one puppy had  one or two worms so I decide not to use that method again.
Prior to that I have only used a wormer and anti flea product just before she became pregnant , Advocate and then panacur whilst she is lactating and of course the puppies as is recommended by manufacturer.
This time I have been advised by my vet to give her Stronghold.  She is day 54. The reason for Stronghold, which is licensed for pregnant and lactating bitches, is to cover her for ear mites, worms, mange etc before the puppies are born. We have lots of foxes that run through our garden and so I want to protect her from what they might be carrying. For some reason I am reluctant to use it but another part of me wants to protect her so she does not pass any ear mites etc on to her pups which has happened once before. I am worried that Stronghold might hurt the puppies although the guidance on using the product states very clearly it is fine to use. Opinions please?

I wormed and brought boosters up to date if needed, before our bitches were even mated.  And then wormed at week 2 after the puppies were born, at the same time the puppies had their first worming.    I wouldn't feel happy to worm a pregnant bitch, whether deemed ok (for the wormer) or not.

I always worm with Milbemax a week or so before mating and then start with panacure at 2 weeks post whelp. I wouldn’t be happy giving any medication to a bitch in pup.

I most definitely would not be using Stronghold with a bitch in pup.  There is no mention of safety during pregnancy on the data sheet for the product:  http://www.noahcompendium.co.uk/?id=-458354

Furthermore, it's just not essential.  Why put any drugs or meds on a dog/give them to a dog during such a sensitive time as pregnancy unless you really really have no other option and/or you perceive there is a real risk to the dog, if not treated?? 

I've never heard of ear mites being transmitted by walking through grass that foxes have been on, to be honest. 

If you want to worm, then use Panacur from day 42 of pregnancy - and only Panacur.  That treats for roundworms, which are a known concern in puppies.  Ear mites and all kinds of unlikely parasites are not known concerns during pregnancy...

Lastly, if you used Panacur during pregnancy and you still saw a worm or two when you wormed the pups at 2/3wks old, then I would most definitely be worming during pregnancy with Panacur again - because you have proof that the bitch has a worm burden and has encysted worms which WILL develop during pregnancy and transmit to puppies.  If you treated with Panacur and saw 1-2 worms at 2wks, then think how many more you will see, if you DON'T treat. 

Knowing that a bitch has a worm burden and has had worms ever in her life, is one indication that you should choose to worm that bitch during pregnancy.  But Stronghold - no.  Worm with Panacur.

I never worm during pregnancy. I worm just before mating, and then when the pups are wormed for the first time at 2-3 weeks with Drontal puppy.

I have always used Panacur 10% from day 42 until 2 days post whelp.   Puppies are born virtually worm free. 

Every single litter thrived, and I would use it again in a heartbeat.

> I have always used Panacur 10% from day 42 until 2 days post whelp.   Puppies are born virtually worm free.  <br />

So are mine (going by what I don't see when the puppies are first wormed, at 2 weeks) when my bitches were wormed before being mated...!