Will you experience loss of sensation in a breast reduction procedure?

Generally not: It depends somewhat on what technique is used, but most techniques should not cause any permanent loss of sensation. For very large reductions, sometimes the nipple/areola complexes are removed entirely and then replaced as skin grafts. In these cases, there will be no sensation in the grafted tissue, but these techniques are becoming less and less common.

It is possible: Any surgery can lead to temporary loss of sensation but most commonly there is complete return to normal although it may take months or even years. With breast reduction the vast majority of patients will have some temporary numbness but the majority will also regain full sensation within 2 years.