
I'd suggest that it won't come back as fast as coming off a litter born into the Winter - when there's max. growth going on!!
Although once mine were retired from showing, and into maternal duties, it didn't matter, I had one who whelped a litter in mid-August and was looking good enough to go to Crufts the following year which was a waste of effort as that was one of the very few shows she wasn't even placed in. She'd taken 2nd in Limit out of 12 the previous year, and was 2nd Open RBCC the year after that!!
I'd just concentrate on helping her rear her puppies, feed her well and exercise her when the puppies have gone, and see how she looks then.