I'm just contemplating this as I can no longer fit into my usual size jeans! I don't think it's fat - I actually think my pelvis has widened since giving birth to DD2 in April this year.
I have 2 amazing DDs; this is absolutely not a sombre thread about me lamenting how my body has irrevocably changed. I'm just remembering that I got away scot-free after DD1 - back into usual sized clothes/jeans 6 weeks after delivery. But it took longer after DD2 (about 12 weeks) and I'm still one size bigger on my lower half. I'm only 3lbs heavier than before I got pg second time and only 3 years older, and I reckon this is a physiological, anatomical change in my body having carried 2 babies to term.
My DH says prefers my body now, and I think I do, too. I'm just quite amazed/taken aback by at the changes.