Increasing Low Birth Weight in America

Copyright ã 1997 by James Michael Howard.

See New: Preterm and Reduced Growth and Development

The AP (Chicago) reported that "The percentage of U.S. women getting prenatal care has risen markedly since 1980, which should be good news, but the overall rate of babies being born with low weight has worsened, federal researchers said." This is derived from J Am Med Assoc 1998; 279: 1623. An editorial accompanying the JAMA article suggests "blacks and the poor - get no more care than previously..." This may be the reason, but I want to suggest another explanation, a biological explanation.

My work suggests human evolution is the result of increased testosterone in our species. Human males and females produce more testosterone than chimpanzee males and females, respectively. Furthermore, my work suggests testosterone increases periodically in civilizations. That is, where food and shelter are beneficial, people of higher testosterone will increase rapidly, compared to low testosterone people. They are more sexual and impulsive; they make more babies. They are bigger and reach puberty earlier; this is known as the secular trend. The secular trend is not due to better food. Black girls reach puberty much earlier than white girls, and there is no support that black girls eat better than white girls. We are currently witnessing an increase in testosterone in America.

Exposure to testosterone, during pregnancy, results in increased probability of low birth weight. This has been tested. Prenatal testosterone exposure reduced body weight of fetuses and newborn rats (Arzneimittelforschung 1984; 34: 780). Another study in sheep found that both fetal survival and growth were markedly impaired by prenatal testosterone administration (Metabolism 1978; 27: 253). Even more ominous is the finding that alcohol and testosterone, combined, induced low birth weight in rats (Tetratology 1989; 40: 335).

Testosterone is higher in black women than white women. "Serum testosterone was greater in AAF [African-American females] than in CF [Caucasian females]." (J. Clin endocrinol Metab 1996; 81: 1108). Low birth weight is more common among blacks than whites. More specifically, the numbers of high testosterone women are increasing more rapidly than the numbers of lower testosterone women. I suggest the JAMA findings indicate that the numbers of women of higher testosterone, and their problems with low birth weight offspring, are increasing rapidly, and increased prenatal care may not be a solution to the problem.