Young women who have malformative breasts logically ask themselves the question of the functionality of their mammary gland and future breastfeeding. Several surgical techniques are possible and the ones that seem to hinder breastfeeding the most are breast reduction and breast prosthesis. Insufficient lactation is a quantitative milk disorder where the mother is unable to ensure sufficient milk production or transfer. It's clear that the calculation of its rate is today the best indicator to evaluate the lactation function. There are still very few studies using this criterion, but their results confirm an alteration in lactation whether after reduction or augmentation breast surgery. It's important to inform patients of the difficulties they may encounter, a high probability of mixed breastfeeding and a shorter duration. But also on the effects that a pregnancy can have on the aesthetic result: decrease of firmness, ptosis, modification of the volume.