They were Katies brand XXL - that equates to a Katies size 20
The pants are 8 sizes larger than her tank top -
from the Katies sizes website:
2XL - Bust 116 - Waist 99 - Hip 126
ABC was wearing a BONDS jumper size XL:
The BONDs sizing for that garment size XL is:
Bust 102 - waist 83 - Hip 108
This equates to a size 16
The tank top with incorporated bra gives a better indication of ABC's authentic size - it was a 12.
A size 12 is: Bust 92
As you mentioned AAAA - If someone had just grabbed a pair of track pants to put on her - they may not have realized that they were pants that Allison had for her pregnancy - but didn't wear now.
But track pants 8 sizes larger are a huge difference - she could not have kept these pants on whilst running - seriously, they would have slid off when running unless they had a cord on them, and even then they would be terribly uncomfortable and impractical to do any exercise in.
And the brand - Katies?
I wonder if Allison had any other items in her wardrobe from Katies?
Its a brand that is known in Australia and has been around for many years - but is not now a fashionable brand, nor a maternity based fashion brand, though it does cater for larger sizes.
... Unless the pants did not belong to ABC at all.
.
I don't think the pants did belong to Allison, and much larger pants would be so much easier to put on a body. That is why shrouds are used, they are voluminous and only require the arms to be put in,