| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Letters to the Editor |
Departments of Medicine and Psychological Medicine University Hospital of Wales Cardiff, Wales, UK CF64 2XX
We were interested to note the articles by Amino et al. (1) and would wish to add to the debate. We have shown that at least 50% of TPO Ab +ve women (as ascertained at a 16-weeks gestation) will develop postpartum thyroid dysfunction (PPTD) (2), the figure being even higher as quoted by Amino et al. (3). However, there is a problem of those TPO Ab -ve women who have been reported to develop PPTD (4, 5). This gives rise (in our opinion) to a falsely high figure for the incidence of PPTD. For example, in the study by Fung et al. (4), often quoted, the incidence of 16.7% was arrived at because of the apparent low but significant incidence in TPO Ab -ve women (who, of course, make up 90% of pregnant women). We believe that this and some other studies should be reevaluated because of the possible false -ve TPO Ab assays. If the data of Kujipens et al. (5) are extrapolated to the general population it would imply that one third of all PPT occurs in TPO Ab -ve women. Not only is this not our experience, but in our prospective study of Ab +ve and Ab -ve women during pregnancy and into the PP (2, 6), not alluded to by Amino et al. (1), we found that none of the 150 Ab -ve mothers developed PPTD during monthly observations for one year. We suggest that the figure should be 0–39% of women who develop PPTD may have been Ab -ve (were the sera re-assayed?). We agree with Amino et al. (1) that it would be useful to screen for TsAb, but the current assays are too expensive and only measure binding Igs. An assay such as the recently described luminescent assay for stimulating antibodies (7) may be appropriate for the future if it could be automated to reduce the cost.
We recognize that there are still data required on the natural history and possible interventional strategies of PPTD to completely justify screening. However, we do not feel, as Amino et al. (1) do, that: 1) because there is a lack of knowledge of follow-up we should not screen (what about congenital hypothyroid screening?) 2) "if symptoms are severe enough ... then clinicians should test for thyroid dysfunction anyway"—in our opinion, this negative attitude will not help to identify patients—how severe is severe and how long the duration? 3) the symptoms are "notoriously difficult to separate...."—surely this is exactly a good reason to screen. Amino et al. (1) ask which thyroid antibody assay should be used; we suggest TPO Ab is currently the most sensitive, albeit only 50%, and we are currently performing a study to improve the prediction of PPTD that would obviate the need to perform TSH assays in at least 50% of TPO Ab +ve women PP. They raise the question of the purpose for screening. First, there is an excess of mild to moderate depressive symptomatology in TPO Ab +ve women (around 30% of the depressed women required psychiatric attention with or without psychotropic drugs in our study). A recent randomized double-blind placebo-controlled trial of T4 0.1 mg administration to TPO Ab +ve PP women between 6 and 24 weeks failed to reduce the incidence of psychiatric disturbance (8). Second, although the follow-up studies cited by Amino et al. (1) show progression to hypothyroidism similar to the Whickham survey, we have recently completed a 6.5-yr follow-up (9) (submitted for publication) showing a minimum rate of 3.8% PP TPO Ab +ve women but a maximum rate of 7.1% PP women who had PPTD during the first year.
A further reason to consider screening for TPO Ab during gestation is the finding published in this journal by Pop et al. (10) documenting a 10-point decrement in IQ in children born to mothers known to be anti-TPO Ab +ve at 32 weeks gestation. These workers have also shown significant psychological impairment in infants born to mothers with low normal FT4 in gestation from an iodine-sufficient area (11). Recent data from a much discussed study by Haddow et al. (12) have suggested a TSH screening strategy in early pregnancy to prevent subsequent psychological impairment in children.
Amino et al. (1), in our opinion, presents a more balanced view, and we have commented on the points raised in his conclusion that lead him to the view that screening all pregnant women is untenable. Education alone will not improve significantly the detection rate of PPT. Refinement and economic automation of the TPO Ab assay will, together with more data on quality of life during this important period, result in trial application of screening for PPT during gestation. In the UK, we still screen for syphilis (incidence? one in a million!).
Footnotes
Accepted August 13, 1999. Address correspondence to: B-Å. Bengtsson, M.D., Ph.D., Professor, Research Centre for Endocrinology and Metabolism, Sahlgrenska University Hospital, Goteberg S-413 25, Sweden.
Accepted June 24, 1999. Address correspondence to: Clemens Kirschbaum, Center for Psychobiological and Psychosomatic Research, University of Trier, Universitaering 15, Trier D-54286, Germany.
Accepted August 19, 1999. Address correspondence to: Paul A. Komesaroff, M.D., Ph.D., Baker Medical Research Institute, P.O. Box 6492, St. Kilda Central, Melbourne, Victoria 8008, Australia.
Accepted August 3, 1999. Address correspondence to: André J. Scheen, Division of Diabetes, Nutrition, and Metabolic Disorders, Department of Medicine, CHU Sart Tilman, B-4000 Liege, Belgium.
Accepted July 26, 1999. Address correspondence to: Christopher T. Cowell, Pediatric Endocrinologist, The New Children’s Hospital, Corner Hawkesbury Road and Hainsworth Street, Westmead 2145, Australia.
Accepted August 18, 1999. Address correspondence to: Vincente Gilsanz, Radiology Department, Children’s Hospital Los. Angeles, 4650 Sunset Boulevard, M.S. 81, Los Angeles, California 90027.
Accepted July 30, 1999. Address correspondence to: Marie-France Kong, Department of Diabetes and Endocrinology, Nottingham City Hospital, Nottingham NG5 1PB, UK.
Address correspondence to: John H. Lazarus, Department of Medicine, University of Wales College of Medicine, Llandough Hospital, Penarth, Cardiff, UK CF64 2XX.
Received August 10, 1999.
References
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Endocrinology | Endocrine Reviews | J. Clin. End. & Metab. |
| Molecular Endocrinology | Recent Prog. Horm. Res. | All Endocrine Journals |
