Well...i know you said coming back other than for having a baby...but I thought I'd throw my two cents in anyway...
I quit (or paused rather) my program when i got pregnant. I always planned on coming back as I had only lost about half of my goal, so I'm not exactly what you're talking about, but I didn't intend to gain back everything i lost plus some.
SO my lesson learned is don't make excuses. A baby/pregnancy is a great excuse...but so are many many other things that come up in life. What i learned is that no excuse is worth gaining back weight that I worked hard to lose. I don't think there was any other one reason that i gained my weight back other than i felt like i had a good excuse.
I hope you get good feedback from others
Good luck on stab/maint. I'll be there someday...