I've asked about pros and cons to breast aug prior to children before, what's a good time span between implants and pregnancy?

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.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).

To my knowledge, there have been no studies as to how long you should wait after a breast augmentation to get pregnant. Thinking practically, I would wait until all of the swelling is gone and your body has "walled off" the implants with at least a fine layer of scar tissue. This would be 3 months or longer. The risk is an increase in the percentage of capsular contractures, which you do not want.
Remember that with or without implants, your breasts will change following pregnancies. Generally, you will probably sag and lose breast volume. 
Women have children into their late 30's or even early 40's. In the meantime, you can enjoy having the breast implants for years or even decades, according to your present age. You may want an uplift after pregnancies with or without implants. 
Excellent question. Good luck.

Only you can determine the best time to schedule your breast augmentation.  Pregnancy will obviously create a lot of changes in your body, especially in your breasts.  The implants themselves will not change but your breast tissue will.  There is no way to predict what your breasts might look like after the pregnancy.  You might need another surgery afterwards to improve the look of your breasts.