Back to work! Thank you for your forebearance while we wrote a chapter for a nursing textbook!
During the course of pregnancy, the mother/fetus dance is ongoing. The maternal immune system and the trophoblast cells continue to influence each other even beyond the implantation.
Because the mother’s immune response modulates near the start of each trimester, the fetus is affected to some degree and mounts a response, as well. For a long time it was thought that maternal and fetal DNA material was not exchanged across the placental membrane, however recent findings indicate that there is some exchange of material. Thus, we all carry some portion of our mother’s DNA and our mother carries some of ours.
What is the impact of this chimeric effect? It depends on how well our DNA gets along!
How does this affect the fetus in utero? The fetus may be affected by clotting issues. Depending on maternal health status s/he may be subject to a stronger or weaker immune system.
How does this affect the mother? Women are more likely than men to develop autoimmune disorders (pregnancy playing a role here), and those who bear male offspring are more likely than those who only have girls to have these disorders.
Please refer to February 5 entry for complete graphic. The Precondition we will discuss today is Genetics.
There are genetic factors totally outside your control that determine things as simple as your offspring’s hair or eye color, how the earlobe attaches to the side of the head and whether or not s/he can roll the tongue. More complex things, such as a predisposition to types of cancers, bleeding disorders or various other diseases, also have a genetic basis.
Because the male contributes the sex of the offspring, once conception happens, the sex off the fetus is determined — at least genetically. But, it turns out not everything genetic is set in stone. In utero, hormone exposures may affect how male and female characteristics develop, so that some girls will be very girlie, some will be tomboys, and some may be gay. A similar effect will influence how boys develop.
Genetic, environmental and behavioral preconditions can be intertwined. Environmental factors can alter genes, causing them to express proteins that would otherwise be dormant. Likewise, our behavior affects some of our genes. If we have a family propensity for heart disease, but we eat a healthy diet, exercise and avoid risky behaviors, we alter the impact of our genetic code.
Keep in mind that some things will be completely determined by genes. It is not reasonable to hope, for example, that our offspring will be 6′5″ if both parents are short (or vice versa). If the mother has “thrifty genes” — that is, genes that make it easy for her to gain weight — she may well do so during pregnancy, even if she follows a reasonably healthy lifestyle. If the immune systems of both parents have some similarities, it may affect the maternal immune response to the implanting trophoblast cells, thus affecting the placenta and, indeed, the entire pregnancy.
So, how do we advise people who are thinking of pregnancy to prepare themselves for a healthy pregnancy genetically? Surely, to determine all the potential genetic possibilities is not feasible or affordable at this point. Maybe in another century! But, we can know some factors: Is there sickle cell anemia in both families? Is there a Mediterranean type of sickle cell disorder? What about clotting factors or differences in Rh? What about diseases or disorders that are not common, like ALS? These are things that potential parents may want to discuss.
Like so much of life, we can’t know everything. There are no guarantees. There is a lot to be learned still about human genes and how they work.
This blog has at its heart the notion that physical activity has tremendous benefits for mother and offspring…and for partners, too. How does the genetic component affect this? First, preconception fitness lowers some risk factors for mothers and babies. Second, each mother’s genes will make it easier or more difficult for her to enjoy or benefit from the activity of exercise. We appreciate this and encourage young moms-to-be to find something enjoyable that you like doing and find people or situations that support you in being active now before you become pregnant.
If you need assistance or advice, please go to www.dancingthrupregnancy.com (use the BlogRoll)
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