New Research Shows Pregnancy Can Alter The Structure of One’s Brain

Scientists once linked maternal behavior to hormones released during birth, but new research shows those changes take place during pregnancy as well.

New research conducted at the Francis Crick Institute in the United Kingdom is changing scientists’ understanding of the hormonal and emotional changes that take place during motherhood.

The study, published Thursday in the journal of the American Association for the Advancement of Science, examined the brains of female mice. Late in pregnancy, the hormones estrogen and progesterone are released. Both hormones affect an area of the hypothalamus associated with parenting: estrogen by making neurons there more sensitive, and progesterone by constructing new synapses that facilitate activity in that region of the brain.

Scientists found the activity made the rodent mothers more caring and attentive towards their pups.

"We think that these changes, often referred to as 'baby brain', cause a change in priority,” said Jonny Kohl, the researcher who led the study. “Mothers need to perform robust parental behavior to ensure pup survival. What's fascinating is that this switch doesn't happen at birth – the brain is preparing much earlier for this big life change."

“We know that the female body changes during pregnancy to prepare for bringing up young… Our research shows that such preparations are taking place in the brain, too.”

We sat down with @monaca97, @ammari_Rachida and @jonnykohl to ask them about their findings, published yesterday, showing that pregnancy hormones ‘rewire’ the brains of mice in preparation for parenthood 🐭
Read more about the study here ⬇️https://t.co/qKTEMoHF76 pic.twitter.com/UKLg7nWNdo

— The Crick (@TheCrick) October 6, 2023

Researchers found the changes in the brain helped alter maternal behavior as well as creating increased “plasticity” allowing mothers to more effectively learn through “trial and error.” The findings may have implications for understanding maternal mental health and treating conditions like postpartum depression.

The study adds to a growing body of research on the biological changes that take place during parenthood for both mothers and fathers. Research last year found fathers also develop increased “experience-induced brain plasticity” in the process of caring for an infant.

Interestingly, caregiving fathers in regions of the world like Spain where men enjoy longer paternity leaves showed more pronounced changes to areas of the brain associated with parenting. Research has also shown that primary male caregivers in gay relationships show greater changes to these brain regions versus secondary male caregivers.