Pregnancy and the Brain: Behavioral and neural
adaptations in a sensitive transition period
Written by Elisa Rehbein and Ilena Bauer
The University of Tübingen and the University of Uppsala are carrying out a study in which maternal
and fetal changes during pregnancy and the infants’ development after birth are investigated. This
will shed light on a sensitive phase where all of our life started.
Pregnancy is a crucial period for wom-
en and is associated with behavioral
and neuronal adaptations presumably
preparing them for the protecting and
nurturing demands of motherhood.
The origins of altered brain anatomies
associated with major mental dis-
orders are assumed to already take
place during the intrauterine phase. It
is important to not only address the
impact of pregnancy on the expecting
mothers, but on fetal development,
child behavior and mother-child in-
teraction. It is necessary to shed more
light on this critical period in a wom-
an’s life that not only shapes her (and
her brain) but also lays the foundation
for her child’s health.
While data on how pregnancy and as-
sociated fluctuations in sex hormone
levels affect brain function and struc-
ture in animals has been collected
throughout the last decades, evidence
on the impact of human pregnancy on
behavioral – but more interestingly
– neuronal adaptations is scarce [1].
Sex hormones are known to act as an
important regulator of neuronal mor-
phology. Not surprisingly, other en-
docrine events involving less extreme
and rapid fluctuations in hormone
levels than pregnancy are known to
render structural and functional alter-
ations in the human brain. The produc-
tion of gonadal sex hormones during
puberty for example regulates an ex-
tensive reorganization of the brain [2]. period and follows a rapid, orches-
trated chain of partially overlapping
ontogenic events. It is highly likely
that the intrauterine milieu can influ-
ence neurodevelopmental trajectories.
These effects may independently, or in
conjunction with other factors, impact
subsequent long-term susceptibility
for various neuropsychiatric disorders.
Moreover, neural alterations have also
been observed in response to even
subtle changes in endogenous or ex-
ogenous sex hormone levels later in
life [3]. Growing evidence has accu-
mulated that the origins of structural
alterations characterizing mental and
neurodevelopmental disorders can be
traced back to the intrauterine period
of life. During this period the develop-
ing fetus (and its brain) is influenced
by environmental conditions during
sensitive periods of cellular prolifera-
tion, differentiation, and maturation
to produce structural and functional
changes in brain and peripheral sys-
tems i.e. fetal programming [4]. Hu-
man brain development begins early
in gestation, occurs over a protracted The Neuronal Emotion Regulation
Network in Pregnancy
While the influence of fluctuating
hormonal levels, such as during the
menstrual cycle, are known to render
structural and functional alterations
in the human brain, knowledge of
changes during pregnancy are surpris-
ingly scarce [5]. However, recently a
study has shown long lasting changes
in brains of mothers in which reduc-
tions of grey matter were still visible
18 months after they had given birth
[6]. Thereby, they were able to predict
which of the women that took part in
their study were pregnant with up to
95.6 % accuracy. Interestingly, reduc-
tions of brain matter lay in areas
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