Did you know that a pregnant person’s immune system responds differently depending on whether the fetus is a boy or a girl? Did you know that multiple sclerosis can go into remission during pregnancy? Did you know that some fetal cells migrate to the brain of a pregnant person and stay there for the rest of the person’s life with potential implications for long-term brain health?
A review of scientific literature on maternal health, “Beyond Sex Differences: Short- and Long-Term Effects of Pregnancy on the Brain” recently published in the journal Trends in Neurosciences, explores this chronically understudied area of research and finds evidence of major changes in short- and long-term neuroplasticity in the brain, inflammatory signaling and cognition. It also finds many intriguing associations with as yet unknown significance that could have far-ranging implications for future treatment and research, all of which speak to the need for further research into sex differences in mental health.
Why do the tiny hairs in each human cell become shorter depending on how many children a person has had? Could that have implications for the aging process? Is there an association between how many children a person has and the risk for Alzheimer’s disease later in life? Why do people who have complications during pregnancy have greater risk for cardiovascular disease, stroke, and Type 2 diabetes later in life and what can be done to reduce those risks?
“Historically in terms of medical research the view has been that females are just males with ovaries,” says lead author CAMH Senior Scientist and Treliving Family Chair in Women’s Mental Health Dr. Liisa Galea. “That is a simplistic view and one of the reasons why it has been so undervalued and understudied.”
On this World Maternal Health Day, Dr. Galea explains why studying maternal health is so important:
What was the purpose of this review? What were you hoping to find?
We wanted to draw attention to the fact that pregnancy itself changes the brain both short term and long term and look at how that may influence health. Women’s health in general is understudied, and one such area is how pregnancy affects the brain after the birth of the baby. Our lack of attention to women’s health costs lives and costs society. Science needs to prioritize the inclusion of female health variables such as pregnancy history to have a complete understanding of what drives risk and resilience for health and disease.
Do you believe this is based on a false premise that gender distinctions in neuroscience are trivial and not worth studying?
The short answer is ’yes’. It turns out that sex and gender matter for all health. There are differences between sexes in cancer outcomes, bone fractures, lung disease and cardiovascular disease, as well as brain diseases. What can we learn from studying female-specific experiences like pregnancy? Multiple sclerosis (MS) often undergoes remission during pregnancy. What is it about pregnancy that may be causing that? Could that lead to new therapeutics for MS for men, women and gender-diverse individuals? There are clinical trials going on right now. The other way to think about it is that by ignoring the influence of female-specific experiences or sex and gender we are missing this richness of information that can inform our knowledge of new treatments. Maybe part of why we don’t have solutions to illnesses we have been studying for years is based on this one-size-fits-all approach.
Talk about what is sometimes called “baby brain” and the evidence that grey matter does shrink during pregnancy.
Total brain volume does decrease during pregnancy up until childbirth. But it does bounce back within six months. It turns out while total brain size doesn’t change after pregnancy, different areas in the brain do change quite a bit, as some are reduced but others are increased. In fact, those reductions in grey matter are related to better communication between different cell pathways and greater maternal attachment. You can think about the reduction in gray matter as perhaps noise reduction – more is not always better!
Are there implications for more specific women’s health issues like postpartum depression or psychosis?
What’s fascinating to me is that a lot of the biomarkers for depression are mimicked in the postpartum period. Maybe it’s not so surprising that we see the greatest risk to develop depression during the postpartum period because it’s like a perfect storm. If you are already more susceptible to depression, the biological outcomes after pregnancy may tip the balance. A number of countries have strategies to deal with the postpartum period to improve the lives of the birthing parent and the family. Unfortunately, Canada is not one of them and we really have to step up.
How does the sex of the fetus impact the health of the mother?
One factor is that if you are pregnant with a boy, he’s an XY (chromosomes) and you’re an XX, so it can impose a greater inflammatory challenge. It might have different pregnancy repercussions than if you are pregnant with a girl. It’s astounding to me that the few researchers who study maternal health do not consider fetal sex as an important factor.
Does this study go to the heart of the womenmindTM mandate?
Yes, womenmind is a community of philanthropists who really want to raise awareness about the gender gap in science, advance research on the mental health of women and girls, and to advance women in science. This area of science is very understudied. We have to ask ourselves, ‘What else are we missing?’
Our paper puts it best:
“Only when the scientific community prioritizes female health by including the variables that matter to female health will we begin to close the research gap between the sexes…Realizing the promise of precision medicine requires attention to how female-specific factors influence health outcomes.”