Will pregnancy post BBL ruin my results?

Hello,
Your body will change with pregnancy. It's difficult to say if it will 'ruin' your result as everyone reacts differently to pregnancy. 
All the best,
Dr. Blagg
Austin, TX

The fat transferred to the butt will be affected by the total body fat percentage, and the buttock will likely get larger with pregnancy and decrease in size with weight loss.  The shift in fat distribution is permanent and will be apparent even during pregnancy and after.  However, if you go through a pregnancy, the skin will lose some of that elasticity.  This loss of elasticity will occur whether you have the liposuction or not.  Very few women have good skin after pregnancy, but you may be one of the lucky ones. Kenneth Hughes, MD, Board Certified Plastic SurgeonLos Angeles, CA

When considering the timing of cosmetic surgery, it is important to note that the longevity of the result is dependent upon your post op stability. Significant changes in weight can alter results. These changes are difficult to predict but they may require revisionary surgery.
Thus, when considering pre-pregnancy surgery one must be comfortable with the prospect of a compromised outcome. In the case of BBL, the significant weight changes can lead to skin stretch and loss of elasticity. There is also the potential for unintended weight gain which persists post partum.
Post pregnancy is an entirely different situation. It is always best to exhibit restraint in the post-partum period. This is due to the fact that your body is changing dramatically during this period. The hormonal fluctuation can alter size and shape widely during the immediate post-partum period and can continue through the period of nursing. Body contouring during this period is the equivalent of hitting a moving target.

The optimal candidate for surgery has reached a healthy stable weight. In the setting of a recent pregnancy and delivery this stable weight can take some time to reach. A general rule of thumb is at least 6-9 months post-partum. If you choose to breast-feed through the first year of life you should allow at least three months following the discontinuation of breast-feeding before considering any procedures.
As always, discuss your concerns with a board certified plastic surgeon (ABPS).