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Centre for Evidence-
Based Medicine

Harm: Clinical Scenario

You are a midwife. During your antenatal classes, a woman asks whether it is safe to take Vitamin A supplements as she has heard that there may be a risk of birth defects from supplements containing Vitamin A. She wants your advice on what to do regarding vitamin supplementation.

You tell her you will investigate and you form the question, do pregnant women receiving vitamin a supplements have a higher risk of children having birth defects? You go to the library and search Medline.

What is your advice to her regarding Vitamin A supplements?

Search strategy for Vitamin A and Pregnancy
Type in: Vitamin A. You will see 'exp retinoids'
Type in:

  1. exp retinoids
  2. exp abnormalities
  3. #1 and #2
  4. exp pregnancy
  5. #3 and #4
  6. limit #5 to human
  7. vitamin a.tw.
  8. #6 and #7

You find the article: Rothman KJ, Moore LL, Singer MR et al. Teratogenicity of high vitamin A intake. NEJM 1995;333(21):1369-1373.

Read the article and decide:

  1. Are the results of this harm study valid?
  2. Are the results of this harm study important?
  3. Should these valid, important results of this study about a potentially harmful treatment change the treatment of your patient?

Continue to completed worksheet