Have you ever wondered if there are changes in the brain during maternity? Science has given an answer to this question, and the latest studies reveal that changes do indeed occur in women’s brains during this stage of life.

But what kind of changes occur, mainly? What brain structures are involved? What effect do these changes have on the mother’s behavior? Finally, does the same thing happen in mothers who conceive naturally as in mothers who undergo in vitro fertilization or in mothers who adopt? In this article we will address all these questions.

Changes in a Woman’s Brain During Childbearing

The changes in the brain during maternity are mainly located in a brain structure called the nucleus accumbens. The nucleus accumbens is a very primitive part of the brain, related to obtaining pleasure, gratification and reward .

It activates our motivation and allows our will to guide our actions. It is also related to learning, memory, fear, aggressions, addictions, laughter… and to very basic and primitive needs, such as sex or food intake. Later on we will talk in more detail about this structure and its relationship with the changes in the brain during maternity.

“Hormonal Boom”

The changes mentioned appear as a consequence of the great hormonal movement that arises during pregnancy , and have the direct consequence that mothers “fall in love” madly with their children.

This hormonal movement, which consists of a great synthesis of different hormones, is very intense and abrupt; in fact, it is generally considered to be even greater than the hormonal change that occurs during a woman’s entire fertile life.

These changes occur mainly in the mesolimbic-dopaminergic system of the brain , where dopamine acts as both a neurotransmitter and a hormone. Dopamine is involved in pleasurable behaviors, in the regulation of motivation, in desire and in the repetition of certain behaviors (especially those that are reinforcing for us).

Thus, science points out that during pregnancy a modification of the activity of the nucleus accumbens is produced, as we have seen, a structure very related to the obtaining of pleasure and reinforcement, in this case of the mother. This activity, in turn, is related to the primitive and instinctive behaviour of the mother towards her baby, aimed at caring for it, protecting it and promoting its survival .

The importance of the nucleus accumbens: what does science say?

We have seen how the nucleus accumbens is a brain structure related to different human sensations, needs and emotions; learning, pleasure, motivation, fear…

In relation to it and the changes in the brain during maternity, research carried out at the Experimental Medicine Service of the Gregorio Marañón Hospital in Madrid and the CiberSAM (CiberSAM), by the team led by the researcher Susana Carmona and with the collaboration of the Autonomous University of Barcelona (UAB), points out that the nucleus accumbens undergoes important modifications in its volume during pregnancy . Specifically, its volume decreases.

Research suggests that these changes are directly related to instinctive maternal behavior. This research can be found in the journal “Psychoneuroendocrinology” (February 2020).

Goal: baby survival

As we see, the changes in the brain during maternity are mainly due to the above-mentioned “hormonal boom”, which affects the mesolimbic-dopaminergic system of the brain, mainly, as well as other secondary areas of the brain. These changes mean that the mother’s behaviour is organised to attend almost exclusively to her baby (her development and survival, fundamentally).

Baby “addiction” (love)

The changes in the brain during maternity make us think of a real “addiction” towards the baby, on the part of the mother, since many of the brain areas that do so are activated in the face of an addiction (for example to sex, alcohol, smoking…).

In addition, in the face of an addiction, all the structures and different brain systems are coordinated so that the individual obtains the reinforcement and/or motivation he or she craves.

But, what does this “addiction” translate into, at the brain level? In a study carried out by the Valencian Institute of Infertility (IVI) of Barcelona, with 25 women (new mothers) and 20 control women (who were not mothers), a decrease in the volume of the nucleus accumbens was observed, through magnetic resonance techniques (MRI). The decrease in the size of this structure is related to the aforementioned addiction.

Decrease in nucleus accumbens

The results of this study, which are in line with the results obtained by the same team three years earlier, in 2017, through a study published in Nature Neuroscience , reveal that the decrease and changes of the nucleus accumbens allows the baby to be a more striking, pleasant and relevant stimulus for the mother.

In turn, this fact causes the mother’s behavior to be modified and directed towards protecting, caring for and loving her baby. Such behaviors, logically, would not appear “by themselves” in a woman who has not been a mother.

Necessary addiction?

We have seen how the changes in the brain during maternity basically involve an addiction or “falling in love” with the baby, which triggers a series of instinctive behaviours in the mother, aimed at promoting her integrity and her life (of the baby).

In line with all this, we found a very interesting idea from psychologist Urie Bronfenbrenner, and that states that for a baby to develop properly, there must be at least one adult madly in love with him .

Natural pregnancy, in vitro and adoption

One question that may arise in relation to changes in the brain during maternity is the following: do these occur in all “types” of mothers? That is, in mothers who conceive naturally, in mothers who have undergone in vitro fertilization … well, the answer is yes, in all of them.

On the other hand, in the parents who adopt, this infatuation or “addiction” that we talked about would occur, although the hormonal factors would not play the same role, logically. Neither would the changes in the brain, which would not occur. In cases of adoption, then, more social and interactive factors would intervene with the baby .

Bibliographic references:

  • Carlson, N.R. (2005). Behavioral physiology. Madrid: Pearson Educación.
  • Hoekzema, E., Tamnes, Ch., Berns, P., Barba-Müller, E. et al. (2020). Becoming a mother entails anatomical changes in the ventral striatum of the human brain that facilitate its responsiveness to offspring cues. Psychoneuroendocrinology, 112.
  • Rosenweig, M.R., Breedlove, S.M. and Watson, N.V. (2005). Psychobiology: an introduction to behavioural, cognitive and clinical neuroscience. Barcelona: Ariel.