how does the abdomen tighten during pregnancy?

[Winter]

I mean like upper ab to lower ab or vise versa

[momof2kiddos]

I asked my YMCA fitness director a similair question when I was about 8 mos pregnant. I wondered 'where' my abs went since I was ALL BABY up front. She said that they separate and move to the sides and become part of your obliques during pregnancy. After delivery, they tighten back to the front.Interesting.

[dolphin mama]

Are you refering to contractions during labor? If so, true labor contractions usually start at the center of your back and move towards the front. When contractions get really hard, they squeeze both from the back to front and from top, down.

[vivek]

I seriously didn't quite get your question.
As far as I get it, this means stretching of your skin which happens during pregnancy.
The baby lies in the upper quadrant and around the time of delivery it moves down.
Hope I suffice your query.