I urgently need advice.My dogs went to stay with a relative while we were at a wedding overseas.we have now  been informed that their 2 dogs have mites and to get our dogs checked over.2 of my dogs have been constantly scratching past couple of days and  i thought they mustve reacted to something in the house.Anyway we took them to the vet and he gave them all advocate spot on treatment but one of my dogs is 5 weeks pregnant..i have not treated her yet..i was under the impression this couldnt be used in pregnancy.Has anyone used this and if not what can i use thats safe for her..thanks in advance xxx

The data sheet is outstandingly silent on the subject of pregnancy:  http://www.noahcompendium.co.uk/?id=-446234

But since it says "Do not use in puppies under 7 weeks of age." and "There is limited experience on the use of the product in sick and debilitated animals, thus the product should only be used based on a risk-benefit assessment for these animals." I don't think I would risk it...

Stronghold covers several types of mites, and the datasheet says "Through a reduction in the flea population, monthly treatment of pregnant and lactating animals will also aid in the prevention of flea infestations in the litter for up to seven weeks of age."

If you are worried about chemicals can you give your dog a full bath and leave the shampoo on for at least 10 mins this will kill fleas and mites.  It does't have to be a flea shampoo, any dog shampoo will do it and diluted dawn dish soap is really good particularly for places like between toes etc.

Dawn isn't available  in the uk but is the same as fairy or similar

It is, I bought it from amazon.

I think I might investigate diatomaceous earth in the first instance, something natural - after all, you don't even know if this particular dog has the mites.  I'd treat the others with the Advocate and keep her away from them till it's dry (it should protect them for a month from mites), then keep a close eye on the pregnant dog and perhaps treat with diatomaceous earth...

Ok I stand corrected .most things are available from amazon :) 
I really only commented as I know many uk people have never heard of dawn dish sopa and fairy or other washing up liquid is interchangeable and most have it in our cupboards