October 25th was Max's original due date. Standard practice is to keep babies in the hospital until they reach at least 2000g but the consensus was that Max was stable enough to go home at 1800g. I began making predictions August 25th. I converged on a good prediction scheme on September 9th and the prediction was that he'd reach 1800g on his due date (October 25th). He came home one day earlier.
You can also get the chart in black and white, although it is somewhat bigger.
This is a chart of weights for babies born at various gestational ages. The top line (green) is the 50th percentile birthweight (that is, 50% of babies are born heavier and 50% are born lighter, for a given gestational age). The second line (blue) is the 25th percentile. The third line (red) is the 1st percentile. This means that 99% of babies are born heavier than the weight indicated by the line.
The bottom line (purple) is Max's weight. The dotted line (aqua) is the growth I predicted for him on Setember 9th. He stayed pretty close, I'd say. The prediction was obtained by taking the 50th percentile curve and shifting it over 62 days to the right. This figure was obtained by finding the best average shift for each of the three percentile curves using the data from days 37 to 47 (without day 43) and seeing which seemed to fit the best.
The birthweight percentiles were entered in from graphs in Arbuckle et al, ``Birth Weight Percentiles,'' Obstetrics & Gynecology, Vol. 81, No. 1, January 1993. (Figure 1. Birth weight percentiles for male singleton live births, Canada, 1986-1988.)
If you want to see the raw data, Max's hospital weights consist of 3 columns: day of life, month, day, and weight in grams. The birth weight percentiles consist of 5 columns: gestational age in weeks, 50th percentile, 25th percentile, 1st percentile, and the gestational age in units of Max-days-of-life.
