What Causes Breasts To Sag?

By Jerome Edelstein, MD

WHAT IS BREAST INVOLUTION?Breast involution is a term used to describe a phenomenon wherein glandular tissue (the tissue that produces milk) progressively diminishes while a similar amount of fat increases. When this process occurs it leads to the loss of almost all of the breast’s functional structures. The end result of glandular loss or atrophy is a fattier and less shapely breast – the opposite of perky breasts.POSTPARTUM INVOLUTION OF THE BREASTSInvolution is common with aging, but can also be triggered through the hormonal changes of pregnancy. During the time when a woman is pregnant, the breasts begin to prepare for lactation. The increased estrogen levels that result from this cause breast tissue to grow in size. The rapid growth that occurs during this time (gestation) is known as breast hypertrophy. After delivering a child, the previously high levels of estrogen and progesterone lower dramatically while prolactin increases, triggering lactation for as long as breastfeeding is continued. Women who decide not to breastfeed also see their hormone levels become much lower than when they were pregnant. In either case, the end result is involution and the return of the breasts to their pre-pregnancy state.

When involution occurs the tissues inside the breast begin to shrink, but the surrounding skin does not. This leads to the kind of sagging, “deflated” look that many women experience after having a child. Once breastfeeding (or lactation) has been completed, the body slowly begins replacing diminished fat deposits over several months, restoring the chest to its former size. In some cases, though, the breasts can lose volume and ultimately end up smaller than they were before pregnancy. This is quite a common phenomenon, the result of a stronger-than-average involution process.POSTPARTUM BREAST MYTHSMany people believe that breastfeeding itself is responsible for creating saggy breasts, but research has shown that this is not the case. A 2007 study examined a sample group of 93 women who had been pregnant at least one time before receiving breast augmentation. 58% of the group had breastfed one or more of their children for an average period of nine months (the lowest reported only two months and the highest 25 months). 55% of the study’s participants claimed that the shape of their breasts had become less desirable after their bodies returned to its post-pregnancy state.

Despite what many may suspect, the plastic surgeons conducting the survey found that the loss of ideal breast shape was not significantly linked with pregnancy weight gain or a history of breastfeeding (including factors such as how many children were breastfed and for how long). There was a much higher correlation between breast sagging and age, smoking, having a larger pre-pregnancy bra size, body mass index and the number of times a woman has been pregnant before. These findings suggest that, contrary to popular belief, breastfeeding does not lead to involution.