Childhood Asthma and Maternal Factors: Have We Hit a Goldmine?
At two-years-old, our middle son underwent what would end up being a non-conclusive colonoscopy, in our attempts to diagnose the cause of his chronic diarrhea. Around the same time, he suffered from eczema—an itchy, red skin rash that made him miserable, and sometimes kept him awake at night. A year after all that, he was diagnosed with asthma—a condition that still plagues him, today. Our youngest son, born at the same hospital as his older brother, also suffered from eczema. His allergic skin rash was so severe that he was literally covered in itchy, red plaques from head to toe.
What Do Asthma and Birth Have in Common?
As we work to get our asthmatic son through the final weeks of allergy season—his breathing compromised by the mold spores currently in the air— I read with interest this article, recently published on Reuter’s Health web site. The article discusses a new study by John Penders, et al out of the Netherlands which suggests a link between mode and location of birth, and a child’s subsequent risk of developing allergies and asthma later in life. More specifically, the study looked at colonization of an infant’s gut with particular bacteria—E coli and C difficile—and found a greater association with colonization of C diff. at birth, and subsequent atopy later in life.
A soon-to-be published cohort study (in the same journal) by Adrian Lowe, et al. looked at another possible predictor of childhood asthma: maternal obesity. 189,783 children born to 129,239 mothers in Stockholm Sweden between 1998 and 2009 were included in this study. The study’s primary goal was to assess the relationship between early pregnancy maternal BMI and subsequent asthma later in life of the children—as judged by prescriptive asthma medication purchase and hospital admissions for asthma.
Statistical regression models revealed a linear relationship between increasing maternal BMI and incidence of offspring asthma—although from my reading of the study, the relationship appeared to be modest, according to the odds ratios provided in the study’s data. Study authors conclude that, “If the association between maternal BMI and asthma risk in the child is causal in nature, it might explain between 11% and 13% of childhood asthma.” (Emphasis, mine.)
Another recent cohort study, published in the Journal of Pediatrics (Tollånes, et al, 2008) looked at the association between cesarean delivery and incidence of childhood asthma. This large (1,756,700 singletons) study out of Norway revealed a 52% increase in asthma incidence among children born via c-section, compared to vaginal delivery.
Application to Childbirth Education and Maternity Care
What do these studies and numbers mean for those of us working with expectant families? Is it realistic to pin the burden of potentially “causing” her child’s subsequent asthma on a pregnant woman of size? Is it realistic to think a laboring woman will contemplate her child’s possible risk of asthma, when faced with the potential of delivering via c-section? No, I would argue, neither of those scenarios are terribly realistic. But what I think these studies do point to is the importance of preconception counseling and guidance: in the form of impressing upon people of childbearing age the importance of preconception good health (including a reasonable BMI for height, build and activity levels) and the continued importance of decreasing the overall cesarean section rate.
More and more studies continue to emerge—not just out of the maternity care research industry, but out of several research fields (pediatrics and asthma/immunology being two)—that point out the importance of normalizing birth practices whenever possible. Ask any family who deals with the frightening circumstance of childhood asthma, and they will tell you: if there had been something we could do ahead of time to prevent our (son/daughter) from developing respiratory disease…we would have done it. Perhaps, we have landed upon a couple of significant opportunities within our own industry to decrease asthma prevalence and incidence. I, for one, would be more than happy to aid in the decrease of childhood respiratory disease. And my son, I think, would be happy about that, too.
Posted by: Kimmelin Hull, PA, LCCE, FACCE