- - click these two little lines, I don't know why but the link became 2 little lines..lol
I don't know if you have these coats in a store near you, because you can't order them online. But they size their coats based on length and start at size 6 and go up by even numbers from there.
The ones I linked for you are the ones made specifically for small dogs, but if you look around the site there are a few other designs as well that start at size 6.
I have seen a size 6 in person and it is really small and would probably fit your baby well. Next time we go to the store that has the one I want (beet twill) we will be buying one for our baby.
The sizing is fairly accurate. Our dog is 9 inches long and we are deciding between size 8 and 10....the 8 is a little short and the 10 is a little big. Sophie is full grown now though, so we don't need to take into consideration her going up a size.
They are pretty expensive but they have a lifetime warranty and they are really nice quality. I don't live in the US but the retailer locator has postal or zip code.
Other than that...I find the xs at Petsmart is sometimes really tiny and may fit your baby.
When Sophie was first brought home we used doll clothes (normally the ones we used were from Micheals), socks cut up and made into a shirt and premie onesies (we just cut them to the proper length).
We didn't spend a lot of money/effort in finding her clothes when we first got her because we knew she was going to grow and the tiny things wouldn't last forever. She is now 2 and a half years old and usually wears a small or extra small, depending on the brand - she was just a little bigger than your baby when she was 7 weeks.