Yes, and no.
Typically "pruning" is done to keep plants small, however pruning techniques can be used on plants in veg to increase the yield of a harvest by forcing the plant to redirect energies.
Take care when pruning however, trimming biomass will reduce harvest. As Jakabok Botch pointed out, more foliage will produce more buds. It is the leaves which grow the buds.
Look into pinching, topping and fimming for techniques that can increase yield. However, when using these techniques the plants will need additional time to recover and take advantage of manipulations.
So, should you prune? If you're willing to give the girls a longer veg period to compensate for the loss in biomass, proper pruning will encourage a bigger yield.