My son was close to 9 pounds, around 22-23 inches long - newborn did not fit him; so he couldn't wear anything that was brought with me to take him home in. My MIL had to buy 3-6 month.

I would either go with 3-6 if what you get is for now - 6/12 for winter.

You can also wait until she has the baby & you know what the length/weight is.

My son was 9 lbs. and 3-6 month clothing was all that would fit him in the beginning, he was wearing 6-12 within the first three months.

I can't say enough about fleece sleep sacks/swaddles for a newborn. Halo is a brand that comes to mind. My DD has 1 year old twins and have been wearing swaddles then sleep sacks since birth. They are so cozy and most babies sleep better when swaddled. There is no need for blankets which are no longer recommended in babies sleeping areas. You can find them at most baby stores, online and even Marshalls and Tj's usually carry them. They come in newborn and small sizes up to toddler.

You might consider a "Bundle Me" - it's really a fleece-lined sack which fits into the Graco-type infant car seats which remove from the car. It's pretty much a one-size fits all and stays in the car seat. My twin grandsons used it - you don't have to overdress the baby on really cold days, just put them into the Bundle Me and fasten the seat belts on the car seat. Although my grandsons were preemie-sized they grew really quickly and were jumbo-sized by 2 months old. They were born in September and were able to use those Bundle Mes until the end of that winter when they were 6 to 7 months old.

Helene

Once you find the perfect gift, I'd buy the same thing twice, in progressive sizes. I'd start with 3 to 6 months size and throw in a 6-12 month size, just to be sure warmth made it through the winter months. I promote growth for babies and like to secure my intentions. LOL!

What a wonderful problem. Welcome to the new baby!

Yes, what a wonderful problem. I like golddust's idea about getting two, especially when it comes to something like a warmth item. Plus, they will get lots of things 3-6 mo so it will be refreshing for them to have a 6-9 also. Also, be sure to include a gift receipt because if you do get two and the smaller one does not fit the newborn, hopefully it would, they can return it and maybe get the 9-12. That way they would still have the item for the whole season.

My daughter was tall, but weight wise little, however around 3 months she took off in growth and we got maybe a months worth of use 3-6 month clothes if even that.

I think the wide range on them is good as it means it should fit up to a 9 month old baby.

I would suggest giving them fleece sleep sack as well. It is great to not have to worry about the baby loosing the blanket on them at night and no chance of getting themselves twisted up in it and choking themselves to death either.

We are still using them for my 20 month old as she can't yet get the blanket back on her.

Thanks everyone! I ended up going with Plan A, the fleece bunting, 3/9M. I got all excited when I saw the Bundle Me, blubird, those are pretty cool! But I learned they already received one of those (which will be very nice for baby!).

Just thought of this so will toss it out... Will the baby be able to wear the bunting in a car seat? If not, it may not get much use.

I like the idea of the 3/9 month size range.

If they already own a BundleMe then they won't need a fleece bunting for the car. The BundleMe essentially remains in the infant car seat ready for the indoor-dressed child. However, my grandkids loved those indoor fleece sleep sacs - very cozy.

Helene

Not reading the responses, so apologize in advance if this is duplicative. I had 3 winter babies very close in age and the Bundle Me was the single biggest lifesaver .... eliminates the need for snowsuits/buntings, etc. Can change a diaper, toss them in the carseat & go. Unzip it so they aren't too warm in the car, etc. and zip it back up to go outside. Love that product. And, one size fits all!
As far as sizing, look at the weight range, because a Gap 6 month (runs big) is not the same as a Ralph Lauren 6 month (runs small), at least in my experience. Babies gain roughly 2 to 4 pounds on average in the first 3 months. I loved getting gifts in bigger sizes as it seems like everyone gives the 3 months size. Something else to consider .... you mention that it is someone very dear to you - a sweet gift that is also a keepsake, unlike most clothes, might be appreciated .... some thoughts are your favorite child's book paired with a stuffed animal or blanket (Good Night Moon is always good), a personalized name stool (something kids will use for many years), bookends or something else for the room, a sweet piggy bank, etc.
Happy Shopping!