Re: Han JY, Choi JS, Chun JM, Park HD, Lee SY, Kim CH et al. 2009. Pregnancy outcome of women transfused during pregnancy with blood products inadvertently obtained from donors treated with acitretin. Journal of Obstetric and Gynaecology 29:694–697

Dear Sir,

I have read this very interesting paper by Han et al. (2009) and I wish to make some comments regarding the validity of the findings.

The paper is very misleading on several counts and should be clarified to avoid readers getting the wrong impression leading to a level of complacency or misuse of these retinoids.

The title of the paper speaks about women transfused during pregnancy, while the description of the cases under material and methods describes women who became pregnant after transfusion. The table has clarified what was done and despite the title of the paper only two of nine women were transfused during the present pregnancy and both of them were transfused in the third trimester.

Teratogenicity of most drugs is mainly in the first trimester. Therefore for the transfusion to have mattered, it would have had to be given during the period of organogenesis during the first 12 weeks of pregnancy or before that time. Anomalies with topical retinoids have only been described with first trimester exposure. Discontinuation prior to pregnancy is adequate precaution for these (Dai et al. 1989). The oral retinoids can however persist in the body long after discontinuation. The short half-life of acitretin and the long period after transfusion to pregnancy 1.3–3 years however, makes it unlikely that any effect would be seen. In fact, the recommendation with the more potent etretinate (longer half life) is to wait 2 years prior to becoming pregnant (Geiger et al. 1994).

The retinoids are believed to interfere with the activity and migration of cranial neural crest cells during development and thus cause craniofacial, thymic, cardiac and central nervous system malformations (Lammer et al. 1985; Rosa et al. 1986). There is also apparently intellectual deficits in more than half the children exposed in utero in follow-up studies to 5 years of age (Teratology Society 1991).

The sample size is also very small with the chance of a malformation from the drug exposure via transfused blood also small; it is unlikely that any effect would have been noticeable in this small cohort.

Declaration of interest: The author reports no conflicts of interest. The author alone is responsible for the content and writing of the paper.