The lactation period is, perhaps, unparalleled in terms of the extent and depth of the metabolic demands placed on the woman over a short period. This makes motherhood a very attractive field of research as it provides researchers with a physiological model of brain plasticity in response to internal and external stimuli. An often overlooked aspect of breastfeeding, however, is weaning or breastfeeding cessation. During weaning, the brain must go through a new set of changes to restore most of its functions to pre-pregnancy and pre-lactation levels. The inevitable offspring growth exerts intense pressure on the mother’s body to restrict its duration and ensure a rapid interruption of maternal behavior and resumption of reproductive functions.
If taken out of context, many brain changes in maternal physiology would be considered pathological at any other time in the mother’s life. These changes include, for example, resistance to leptin, one of the hallmarks of the metabolic syndrome, diminished (and, therefore, potentially insufficient) response to stressors, and excessive volume expansion at the expense of drastically reduced osmoregulation. Consequently, it is logical that mothers may carry imbalances for an unknown period if weaning does not occur properly. Identifying and understanding changes caused by weaning in the central nervous system can provide us the knowledge to better intervene if something goes wrong during this period.
Although it is an underestimated problem, motherhood can be a challenge for many women and leave lasting consequences. Excessive weight gain during lactation may predispose to obesity and cardiovascular risk, even decades after birth. Sleep patterns are altered during pregnancy and nursing, and there is no conclusive evidence on when and if sleep patterns return to baseline levels. Postpartum depression is a disabling illness for mothers that can be as prevalent as 30%, depending on the criteria used. These problems have poorly understood causes, which makes studies focused on the brain processes of lactation and weaning particularly important to unravel the mechanisms behind these conditions.
Therefore, the results of our surveys may be of high interest to all medical professionals working in women’s health, especially those in the field of obstetrics. Our work also plays a broader role in highlighting specific processes in the female brain, an essential step in correcting the chronic under-representation of female subjects in research. Finally, our results should interest the pharmaceutical industry since we have identified a group of individuals (breastfeeding mothers) as at increased risk for inefficient brain restoration of circuits that control sleep architecture and consciousness. We have also identified a neurochemical group directed towards pharmacological intervention to restore normal brain function. Clinical trials can be conducted comparing the efficacy of drugs based on orexin antagonism with other types of drugs used to treat insomnia in women in the postpartum period. These results could then be used to inform public policy on treating sleep disorders in adult women.
Concerning innovation, our research line can be considered an innovation for approaching an underexplored experimental model: the weaning brain. Most works investigate the mother’s physiology and behavior a few days after birth, while our laboratory studies what happens to the mother’s body when lactation ends. This has direct consequences on the market, as medical products aimed at the mother’s health after delivery are minimal compared to those marketed to mothers during pregnancy or to the health of babies. An example of this is the lack of medication to combat postpartum depression, the most common complication of pregnancy. However, postpartum depression is believed to share only part of its etiology with other depressive disorders.