me, found out during detailed scan too.. but i wasnt prescribe with aspirin as my boy only start to slow down in 3rd trimester around 33 weeks and my gynae was not very worried, he just mentioned he will monitor baby's growth.
I did tried to eat more, most of the fats went to me as usual and baby only absorb a bit. I gave birth at 36 week 6 day and he weigh 2.45kg. Look small compared to the babies in the nursery room, in fact he is the smallest size there.
P.S.: He was commented as small by friends and colleagues at 1 month but pediatrician commented he has been growing very well. From 2.45kg to 4.95kg at 2 months old. Is ok to have a small sized baby, can fatten him after birth and I do not need any stitching during my natural delivery as there was no need for a cut. ^^