Discussion Questions

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  What was the study design?

  
  
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  How were the data analyzed?

  
  
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  What were the results?

  
  
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  What are the study’s strengths and weaknesses?

  
  
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  What do the study results mean clinically?

  
  
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  Where should we go from here?

Introduction

Twenty years ago, the US Public Health Service recommended that women of childbearing age ingest 400 mcg of folic acid daily to help prevent neural tube defects in their babies. To further ensure sufficient intake, the government mandated supplementation of enriched cereal grain products by January 1998. This simple measure is associated with a 31% drop in the prevalence of spina bifida and generally, an estimated 1000 fewer cases of neural tube defect per year. Still, about 1500 babies are born with spina bifida yearly in the United States. A new study suggests that basic measurements can predict diagnosis earlier in about half of affected pregnancies.

George A. Macones, MD, MSCE,

Associate Editor

Introduction

Twenty years ago, the US Public Health Service recommended that women of childbearing age ingest 400 mcg of folic acid daily to help prevent neural tube defects in their babies. To further ensure sufficient intake, the government mandated supplementation of enriched cereal grain products by January 1998. This simple measure is associated with a 31% drop in the prevalence of spina bifida and generally, an estimated 1000 fewer cases of neural tube defect per year. Still, about 1500 babies are born with spina bifida yearly in the United States. A new study suggests that basic measurements can predict diagnosis earlier in about half of affected pregnancies.

George A. Macones, MD, MSCE,

Associate Editor

Background

Macones: Thanks for coming to discuss this very interesting article from Bernard and colleagues on first-trimester screening for spina bifida. Leaders in prenatal diagnosis, including the authors of this paper, continue to move diagnosis of specific anomalies earlier and earlier in pregnancy. Can you comment on the importance of early prenatal diagnosis of spina bifida?

Odibo: As the authors point out, the incidence of spina bifida has decreased in developed countries because of supplementation and fortification of foods with folic acid. Still, spina bifida is a common abnormality that is associated with much morbidity, and therefore, it still warrants our attention. I think screening early in pregnancy is particularly important. First, it is possible that those who screen positive could then undergo an earlier diagnostic ultrasound. This could lead to earlier decision-making for parents regarding termination. Second, there could be earlier consideration for fetal surgical interventions. So I think earlier identification is quite important.

Macones: What is your opinion of the measures used in this study?

Odibo: I really like them because they are simple. I believe that for screening tests to be useful, they have to be relatively easy to implement. Relatively simple measures, such as measuring the biparietal diameter (BPD) or the head circumference (HC), fit that criterion for me.