(Symbol image). A second pregnancy leaves its own mark on the maternal brain and affects different neural networks than the first one. Through repeated brain scans of 110 women, a team from Amsterdam UMC documented how structure and function shift over months. The findings also shed new light on the onset of postpartum depression.
(Photo: © Forschung und Wissen)
It has been established for several years that a first pregnancy restructures the brain. A new study from Amsterdam UMC published in the journal Nature Communications indicates that a second pregnancy also leaves its own traces in the maternal brain. Using repeated MRI scans, the team tracked changes in 110 women. Interestingly, the most significant shifts occurred in neural networks that were barely affected during the first pregnancy. These findings could help identify psychological stressors surrounding childbirth at an earlier stage.
Understanding the Impact of Pregnancy on the Brain
Pregnancy is among the most significant biological transformations in a person’s life. Over weeks and months, estrogen and progesterone levels rise dramatically, crossing the blood-brain barrier and directly influencing nerve cells and their connections. Previous research had already shown that the volume of gray matter in specific regions decreases, a process interpreted as fine-tuning rather than loss. This restructuring of the maternal brain is linked to the ability to respond to a newborn’s needs, interpret signals, and establish a strong bond. Up until now, these insights relied almost exclusively on first-time mothers, whereas most mothers experience multiple pregnancies.
This recent study addresses that gap, systematically investigating whether and how the brain changes during a second pregnancy and whether this restructuring follows the pattern of the first or deviates from it. The question is far from trivial, as it touches on the fundamental understanding of female neuroplasticity over repeated life events. In neuroscience, pregnancy serves as a rare natural model for observing how an adult brain restructures itself under extreme hormonal influences.
Different Networks Targeted in Second Pregnancy
The research group led by Elseline Hoekzema at Amsterdam UMC studied three groups over an extended period. One group of women was expecting their first child, another was pregnant with their second, and a third group was childless and served as a comparison. Repeated brain scans allowed the researchers to track shifts in structure and activity over time. In the first pregnancy, the most significant changes appeared in the Default Mode Network, which is involved in self-reflection, social thinking, and processing our inner states. In contrast, during the second pregnancy, this network changed to a lesser extent, while the most notable shifts occurred in networks responsible for attention and responding to sensory stimuli.
This insight challenges the assumption that every pregnancy merely repeats the same restructuring. Instead, each pregnancy leaves its unique mark, shaped by the brain’s previous experiences. The first child primarily establishes the foundation for bonding and perspective-taking, whereas the second focuses on enhancing systems that facilitate simultaneous observation and response. This aligns with the observation that parents of multiple children develop a different style of divided attention. Remarkably, the brain doesn’t just react once to parenthood but adjusts flexibly in response to new demands in subsequent pregnancies.
New Insights into Postpartum Depression
Beyond fundamental research, this work links structural brain changes to the course of peripartum depression—depressive episodes during or shortly after pregnancy. The team found connections between changes in the cerebral cortex and the occurrence of depressive symptoms in both first and second pregnancies. According to the researchers, this provides the first evidence that restructuring processes in the brain during pregnancy are linked to maternal depression. Notably, the timing of these connections varied between groups. With first-time mothers, these correlations primarily manifested after childbirth, while in women with a second pregnancy, they emerged during the pregnancy itself.
Moreover, the emotional bond between mother and child also correlated with brain changes, with this relationship being more pronounced after the first pregnancy than after the second. The robustness of these connections remains uncertain, as the sample size of 110 participants—though substantial for a detailed imaging design—is limited for broader clinical conclusions. Therefore, researchers view their results as an essential starting point rather than a conclusive picture. For practice, this approach offers a prospect for earlier and more targeted identification of psychological burdens around childbirth based on measurable changes in the brain. Understanding the underlying neuroplastic processes may be critical for the prevention and treatment of postpartum depression in the long run.
Nature Communications, The effects of a second pregnancy on women’s brain structure and function; doi:10.1038/s41467-026-69370-8
