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Causes of major birth defects still largely unknown

Causes of major birth defects remain largely unknown, say researchers who studied thousands of cases but could establish a definite cause in only one in every five such infants.

The causes of major birth defects remain largely unknown, say researchers who were able to establish a definite cause in only one in every five infants they studied.

birth
Research is needed into prevention of birth defects. Picture: iStock

While studies have shown associations between birth defects and risk factors such as maternal diabetes, smoking and obesity, translating these associations to actual causes has been difficult.

Researchers at the University of Utah School of Medicine in Salt Lake City in the US set out to establish causes of major birth defects in children born from 2005 to 2009 using Utah state’s population-based surveillance system.

Urgent need

They identified 5,504 cases among 270,878 births, a prevalence of 2%.

Definite cause was assigned in 20.2% or 1,114 of the identified cases. Among these, chromosomal or genetic conditions accounted for 94.4% or 1,052, environmental exposure for 4.1%, and conditions associated with twins for 1.4%

The remaining 79.8% or 4,391 were classified as unknown. Of these, 88.2% or 3,875 were isolated birth defects. Family history, meaning similarly affected first-degree relative, was documented in 4.8% or 266.

The authors say the findings highlight an urgent need for better research as a basis for prevention and care.


Feldkamp M et al (2017), Etiology and clinical presentation of birth defects: population based study. BMJ. doi: https://doi.org/10.1136/bmj.j2249

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