February 18, 2009

Pregnancy Pathway, Preconditions — Genetics

dancingthrupregnancy 1 baby, exercise, genetic disease, immune system, offspring, parents, placenta, preconception, pregnancy, prepregnancy, Rh, trophoblast

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.

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