Bought these for my grandchild, who is 7 weeks old and in the 50 percentile for size (22.3 inches and 10.6 lb) I washed them before use. I got size 3 month and they just barely fit. They run on the slim side, especially the arms. It was a real struggle to get the arm through. I would definitely size up. Luckily, we know a newborn we can pass them down to. I will not buy again because of how the sizing runs.

Very slim fit. My son is in the 17% and only 5 months (bought the 9 month) he barely squeezes in! Disappointing to say the least. And since all his clothes get washed before wearing, they can't be returned

They do run small - and the arms / hand opening is oddly tight...but for the price, I still feel they are worth it! My baby is very "average" sized, so I just grabbed the next size up and make sure I stretch out the hand opening before putting them on her.

I bought 2 sets of 3M for my son who is 1½ months. I wash everything befote he wears it and they dont even fit his length. The sleeves seem very narrow as well. I feel like I tossed $30 in the trash.

VERY small! I bought 9month and they're smaller than some of my 6month sleepers. Waste of money! They feel fine, a little on the thin side, otherwise fine. But definitely size up at least 1 size!

I purchased and washed them my 9wk old baby couldn’t even move her legs they were extremely snug on her baby thighs but loose on her tummy and arms , unfortunately these won’t work for us my baby is 12.5lbs and I ordered 3 months

Bought two sizes up, washed once (not worn) ,tried to put them on, way to small. What a waste of money!! Im so unhappy! If i could give zero stars i would

These run small! My 4 month old barely fit in the 6 months. 6 months more like 6 weeks!