PLANETARY HEALTH WEEKLY

Let’s explore what being of low birthweight does to brain development. In my September Blog (#9) on early life I explained how conditions in your early life from conception to age two (first thousand days) are when perhaps half of your adult health is programmed. This suggests that the impact of personal health-related behaviors we practice in later life may not matter as much for our health as we think. Last month we found that being poor is bad for your health, and especially living in the U.S. is not so good for being healthy. Birthweight is a proxy measure of development in the fetal period. Being born of low birthweight compromises how healthy you can become, although like all population health factors, it doesn’t imply that you can’t rise above early life circumstances and be healthy despite having low birthweight.

Attachment issues in the next two years after being born are critical too. A wag once said “choose your parents carefully.” That is not an individual decision but one that societies make. Having national policies that give paid time off once you have a baby promote better health. Poverty in a country is a policy choice. The United States has the most poverty of all rich nations, again because that is something Americans seemingly choose to have.

Let’s begin by looking at brain development issues and how they are affected by early life conditions.

Birthweight & school performance

An important study looked at all births in Florida from 1992 to 2002 and tracked their birthweight with scores on standardized tests in school. One can question whether these tests measure brain development but consider them a proxy indicator.

The New York Times newspaper produced an interactive report allowing exploration of the findings. Those with higher birthweights did better on the tests, peaking around 9 to 10 pounds and then declining slightly.

This graph above illustrates the relationship. The mother’s education also had a major impact as demonstrated on the graph below. 

The range of test scores for mothers that did not graduate from high school showed that at the high birthweight end, the children did not do much better than those at the low birthweight end for mothers who did graduate from high school. Again at the high end, the test scores were comparable to low birthweights of those mothers with some college, and so on to college graduates. 

These graphs apply to populations. The light shades around the blue lines represent ranges, or confidence intervals. It doesn’t mean that if your mother did not get much education that you are doomed to not do well in school. My mother had two years of formal education, my birthweight was 9 pounds, 6 ounces and I did well in school. 

The interactive feature on the website allows looking at racial distinctions and mother’s ages. Babies born to Black mothers had the worst test scores and Asian mothers had the best. Measures of school quality did not influence the results. 

One response to these findings is to make sure mothers graduate from high school or better, from college. However, mothers who themselves were born of low birthweight may not have the brain development to do well in school, and they may not have the economic resources to go to college, which is expensive in the U.S. 

A look at rates of low birthweight of American mothers and their educational status show that Black college graduate mothers have babies with the highest rates of low birthweight compared to any other radicalized group of any educational status. We will discuss the importance of racism in a future blog. 

Consider natural experiments to illustrate the importance of the first nine months. If you were pregnant and near Ground Zero in New York on September 11, 2001 you were more likely to deliver a low birthweight baby. These children have been followed and found to have compromised neurodevelopment. If you were a pregnant Arab woman living in California at that time, you also were more likely to have a low birthweight baby and deliver pre-term. Hurricane Katrina and the Quebec Ice Storm are other examples of disasters affecting cognitive development in the infants who were in utero then. The main takeaway is that development in utero affects brain development significantly. 

Fetal size is related to poverty in the middle-trimester of pregnancy. Other studies demonstrate that poor mothers give birth to babies with compromised brain development. Fathers matter too. Dads who had cumulative early life stress father babies with smaller brains. Research suggests that socioeconomic status before a fetus is conceived matters for later outcomes. The admonition in last month’s blog to not be poor or to have poor parents is what society needs to do. 

We saw in Blog #9 that conditions that foster secure attachment, the sense of an infant feeling wanted and cared for in ways that depend on cultural values during the first few years after birth are critical as well. Early attachment styles can be inferred from the adult attachment interview. Diabetics with secure attachment in early life have lower mortality rates than those with various forms of insecure attachment. Reasons may relate to the biology of those with secure attachment. Attachment also affects outcomes in other health conditions. 

Popular books looking at the importance of early life issues in adulthood include a long-standing best-seller, The body keeps the score: brain, mind, and body in the healing of trauma by Dr. Bessel Van Der Kolk. It has been on the New York Times list for more than 2 years and has been published in 38 languages! Van Der Kolk talks about trauma. As an emergency physician trauma to me was what was observable in the emergency department. Stabbings, car crashes, gun shot wounds, beatings and the like. It took me a while to embrace today’s popular use of the word trauma.

The next blog (December 15) will explore this popular term trauma and how it connects with ACEs or Adverse Childhood Experiences.