I was 36C before children, 38DD while feeding baby 1, 36C after feeding baby 1 (but definitely saggier), back to 38DD when feeding baby 2, then 38D after feeding baby 2. Baby 2 is nearly 2 years old and still 38D (but they are decidedly further south than they used to be!). So mine got bigger!!!
A friend of mine put it well...
"I used to have great tits....until my kids ate them!"