Thursday, July 17, 2008

Day 29

So you are improving in weight.

Here is your raw data.
You were heavy at birth, likely because with an epidural they pump mom with several extra liters of water. You absorb some of that too.
At day 4 you were 6 lbs 10 oz.
Your actual birth-weight is likely between those two
Notice that the early data is sparse.
We weighed you less frequently.
Here is the last several days.
We weigh you before and after every feeding.
The scale is accurate to 0.5 ounces.There is noise in the signal.
There is uncertainty in the scale.
There are variations in your weight.

What is really going on?

So I use RLS (recursive least squares) to get a better feel for the trend.

I used a low learning rate (0.15), an intermediate one (0.8), and in the spirit of SOR and a Hamilton method, one with a learning rate above one (1.5)

You were not gaining weight. An amazing friend of my wife gave her some of her own stored breast milk. We are supplementing and you are gaining.

Note that the low learning rate most characteristically parallels the centerline of the data.
Trimming out that part of the data and fitting an equation to it yielded a good aproximation of your growth rate for the last 3 days. You have been gaining 0.11 lbs or about 1.75 oz per day.

According to kellymom you should gain on average from 0.55 to 0.85 oz/dy but you can go a little lower or a lot higher and be okay. Breastfeeding-essentials says the same.

You are growing, little girl. Thats important.

Oh, we found a portable safe carrier for you for around the house. We can put it in the center of our bed and not roll over you, or worry about it. You seem to find it womb-like, and you sleep well in it. We covered it in a beautiful baby-quilt that my grandmother made for you.

Next time I will try to show you how we figured out what you need in the way of supplemental milk to keep a good growth rate. I will also try to have more amazingly cute baby pictures.

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