From the Editor

Brain structural and cognitive changes during pregnancy

Current Psychiatry. 2023 November;22(11):13-15 | doi: 10.12788/cp.0408

References

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The following cognitive functions increase between the first and second trimester: verbal memory, attention, executive functions processing speed, verbal, and visuospatial abilities. Interestingly, mothers of a male fetus outperformed mothers of a female fetus on working memory and spatial ability.

Other changes^11-16

Cells from the fetus can traffic to the mother’s body and create microchimeric cells, which have short-term benefits (healing some of the other’s organs as stem cells do) but long-term downsides include future brain disorders such as Parkinson’s disease or Alzheimer’s disease, as well as autoimmune diseases and various types of cancer. The reverse also occurs with cells transferring from the mother to the fetus, persisting into infancy and childhood.
Postpartum psychosis is associated with reductions in the volumes of the anterior cingulate, left parahippocampal gyrus, and superior temporal gyrus.
A woman’s white matter increases during pregnancy compared to preconception. This is attributed to the high levels of prolactin, which proliferates oligodendrocytes, the glial cells that continuously manufacture myelin.
The pituitary gland increases by 200% to 300% during pregnancy and returns to pre-pregnancy levels approximately 8 months following delivery. Prolactin also mediates the production of brain cells in the hippocampus (ie, neurogenesis).
Sexual activity, even without pregnancy, increases neurogenesis. Plasma levels of prolactin increase significantly following an orgasm in both men and women, which indicates that sexual activity has beneficial brain effects.
With pregnancy, the immune system shifts from proinflammatory to anti-inflammatory signaling. This protects the fetus from being attacked and rejected as foreign tissue. However, at the end of pregnancy, there is a “burst” of proinflammatory signaling, which serves as a major trigger to induce uterine contractions and initiate labor (to expel the foreign tissue).
Brain levels of the anti-inflammatory cytokine interleukin-6 increase in the postpartum period, which represents a significant modification in the neuroimmune environment, and the maternal brain assumes an inflammatory-resistant state, which has cognitive and neuroplasticity implications. However, this neuroimmune dysregulation is implicated in postpartum depression and anxiety.
Older females who were never pregnant or only had 1 pregnancy had better overall cognitive functioning than females who became pregnant at an young age.
In animal studies, reproduction alleviates the negative effects of aging on several hippocampal functions, especially neurogenesis. Dendritic spine density in the CA1 region of the hippocampus is higher in pregnancy and early postpartum period compared to nulliparous females (based on animal studies).

Pregnancy is indispensable for the perpetuation of the species. Its hormonal, physiologic, neurobiological, and cognitive correlates are extensive. The cognitive changes in the postpartum period are designed by evolution to prepare a woman to care for her newborn and to ensure its survival. But the biological sequelae of pregnancy extend to the rest of a woman’s life and may predispose her to immune and brain disorders as she ages.