How Motherhood Changes You Permanently? Pregnancy Hormones Remodel Specific Neurons in Brain [Study]

Women are changed forever once they become mothers. The changes are not limited to their physique but, most significantly, to their brains.

Pregnancy Hormones Change Women Permanently

It's no secret that becoming a mother changes you forever. Pregnancy hormones flood your body, causing physiological and behavioral changes that help prepare you for the developing baby. However, some of these alterations, like the ones in the brain, remain.

Pregnancy-related changes in the brain's structural makeup have long been recognized. But up until recently, it was unclear how exactly this neural remodeling is carried out. Scientists from the UK's Francis Crick Institute shed light on the molecular foundations of this cerebral circuitry in a new study.

According to Johannes Kohl, group leader of the State-Dependent Neural Processing Laboratory at the Francis Crick Institute and one of the study's co-authors, estradiol and progesterone, two pregnancy hormones, structurally remodel some neurons in the brain by attaching to receptors that can directly switch genes on and off.

To explore these impacts, the team contrasted the behavior of pregnant female mice to that of unpregnant mice. They then discovered a collection of specific nerve cells in the hypothalamus, the brain's coordinating hub, previously linked to parenting behavior.

High amounts of receptor molecules that bind to the receptive hormones estrogen and progesterone were discovered inside these nerve cells.

The pregnant mice's removal from the cells seemed to hinder typical parenting behavior, but it did not impact their virgin counterparts.

They then focused on how the maternal mice's brain activity was impacted by the binding of these hormones to their receptors. The observed effects of estrogen increased the excitability and decreased the basal activity of these nerve cells, but these effects were transient. However, progesterone had a persistent remodeling effect on the animals' brains.

The creation of so-called dendritic spines-tiny protrusions on the information-receiving regions of neurons-occurs in this specific instance as a result of progesterone binding to its receptor. These spines attract fresh inputs onto these neurons, altering how they are incorporated into the brain's parental networks.

To put it another way, progesterone indirectly stimulates the development of new neuronal communication sites. Kohl noted that it is interesting that these changes are long-lasting and appear to remodel the brain permanently. She concluded that pregnancy always changes how these remodeled neurons are integrated into the rest of the parenting network in the brain.

How Unborn Babies Use Their Dad's Genes To Trick Mom's Body

Another study discovered that mouse babies steal nutrients from their moms through the placenta. They copy an imprinted gene they inherited from their dad to tell the pregnant other to focus nutrients on the fetus.

The genes babies receive from their dads promote fetal growth by diverting the nutrients to the fetus. However, the genes from the mothers tend to inhibit this.

According to co-senior author Miguel Constancia, an epigeneticist at the University of California, Berkeley, there is a lot of potential conflict between the mother and the child. She noted, however, that the majority of pregnancies are cooperative.

Constancia asserts that genetic imprinting and hormones secreted by the placenta influence the nutritional "tug-of-war" between the mother and child during pregnancy.

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