I ended up with an umbilical hernia after my first pregnancy (my son is now 3). It turns out that I probably always had one, because I always had a slight 'outie' belly button, and the pregnancy just made it worse (I was 120 lbs. and gained 65 lbs. during that pregnancy, so I was H-U-G-E!!! But weight gain isn't necessarily what causes it.) My OBGYN was able to tell what it was and sent me for a consultation to a local surgeon.
Sometimes umbilical hernias are no big deal and you don't need to fix (like when I was a child). Sometimes the opening becomes large enough that it warrants fixing (as in my case) because it's in essence, a hole in your abdominal wall. In extreme cases, parts of the bowel can come through the opening and cause huge problems. Yuck.
I had surgery to close the opening three months after giving birth. They basically made a small incision near my belly button and inserted a piece of surgical mesh to close it off.
I won't say that it was fun. The recovery SUCKED for two days. I had my husband and mother watching my son around the clock because I couldn't even move from bed except to go to the bathroom. I had to nurse him lying on my side (I was told the pain meds were OK when nursing because it's often the same thing given to moms after a c-section). LOTS of ice packs helped. Turns out that the percoset was way to strong for me and made me very weak. Once I switched to regular advil, I felt much stronger and could move around without getting so dizzy.
Full recovery took about 5 days. I had to wear a bandage for three weeks and stay out of ponds and pools for that long. I ended up getting a dr's order for 3 weeks of recovery and was able to tack that on to my maternity leave.
I got pregnant again a year after surgery and had my daughter that spring. No problems with the surgery 'holding' -- it should last a lifetime.
The only drawbacks I have are mostly cosmetic-- incision scarring and sutures. Some surgeons use a certain type of sutures and I had a lot of scarring under the skin. There's a section around my belly button that sticks out from where the edge of the mesh doesn't lie flat. Let's just say my bikini-wearing days are gone! My surgeon has moved to Fla, so I plan to have another consultation to see if it is necessary to have another surgery to fix it, or if it is something I can easily live with. If you want, I'll keep you posted!