Usually birth weight, however Our doctors use weight at 12 hours for Janelle, born around 34 weeks, it wasn't her absolute lowest, but due to swelling and fluid retention bad enough that she needed diuretics they don't consider her birth weight to be accurate, so they go by 4lbs 8ounces (she was 5lbs 9ounces at birth). I go by 5lbs 9ounces though, that's what I have pictures of the scale saying and everything.... For River, who was born at 36 weeks, no one knows his birth weight, we know his original weight of 6lbs 9oz was wrong, and we know that by what the nurse wrote down for grams instead of lbs (really hard to read) he was right around 6lbs (either 5lbs 14.3oz and 6lbs 0.9oz depending on what we think one of the numbers was) and we know he weighed 5lbs 10oz at 4 hours old, that's all we know...so we go with the 5lb 14oz measurment for everything...the endocrinologist he is now seeing for FTT would like something more accurate...I wish I would of been able to go with him to the nursery and see him being weighed...my dh barely remembers it since he had been up for 24ish hours at that point...
