Wore this on my baby moon (26-27 weeks) in my typical size M (S in Ellies). Because of that, assuming you could maybe size down/go with Ellie sizing when not pregnant? But I also think this will fit postpartum no problem. I Cannot sing the praises of this cotton voile fabric enough. I own a bunch of silk nightgowns because I love me some bougie sleep, but this is so comfortable and so light and beautiful that I would buy one in literally every color, if they made more. Doesn’t look grandma-ish or childish (are those secretly the same category???), just looks like a beautiful midcentury summer lounging nightgown. 10/5 stars.