It's so variable. Some women have it drained once and it settles, others a couple of times and some of us took longer. Mine took 4 months to settle and I had it drained quite a few times. The important thing is that although it may not seem like it ever will, it does eventually dry up and disappear.
My chemo wasn't delayed and I had it drained literally the day of first chemo when my bloods were good and my infection risk low but then I could not have it done again after chemo and before rads. I had minimal seroma fluid during chemo anyway so that was okay. I had the final one done before rads and then it settled down completely.
Don't get disheartened. Hopefully for all of you with seromas this will be a quick process and they'll settle very quickly.
Elinda x