Clinical Pathology Abstracts, 8/17

Create PDF

Editor: Deborah Sesok-Pizzini, MD, MBA, professor, Department of Clinical Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, and chief, Division of Transfusion Medicine, Children’s Hospital of Philadelphia.

Etiology and clinical presentation of birth defects: a population-based study

Birth defects are inborn errors of development and include any structural or functional anomaly that impacts physical, intellectual, or social well-being. They are a considerable and growing clinical and public health challenge. Major birth defects are common and costly. Collectively, they are estimated to occur in one in 33 births, which translates into approximately 7.9 million babies affected worldwide. In the United States alone, the cost of care during a single year (2004) was estimated to be $2.6 billion. Birth defects are the leading cause of infant mortality in the United States, estimated at one in every five deaths in the first year of life. The authors conducted a study in which they investigated cases of birth defects in children born between 2005 and 2009 in Utah as an initial step to characterize the etiology, morphology, and pathogenesis of birth defects. They used Utah’s statewide population-based public health surveillance system, which monitors birth defects among all pregnancy outcomes in Utah residents, for their clinical case review. They found 5,504 cases among 270,878 births (prevalence, 2.03 percent), excluding mild isolated conditions, such as muscular ventricular septal defects and distal hypospadias. The authors measured the proportion of birth defects with a known etiology or unknown etiology by morphology and pathogenesis. Their results showed that a definite cause was assigned in only 20.2 percent of cases: chromosomal or genetic conditions accounted for 94.4 percent, teratogens for 4.1 percent (mostly poorly controlled pregestational diabetes), and twinning for 1.4 percent (conjoined or acardiac). The remaining 79.8 percent of cases were classified as unknown etiology. The authors noted that these findings underscore the gaps in knowledge regarding causes of birth defects. They concluded that for causes that are known, such as smoking or diabetes, assigning causation of birth defects is still challenging. However, they state the importance of studying the impact of these exposures on fetal development so appropriate interventions can be designed. For unknown causes, better strategies are needed, including greater integration of etiology, morphology, and pathogenesis into epidemiologic studies; closer collaboration between researchers, clinicians, and epidemiologists; and better ways to measure fetal exposures.

Feldkamp ML, Carey JC, Byrne JLB, et al. Etiology and clinical presentation of birth defects: population based study. BMJ. 2017;357:j2249. doi:10.1136/bmj.j2249.

Correspondence: Dr. M. L. Feldkamp at marcia.feldkamp@hsc.utah.edu