Department of Obstetrics and Gynecology Fatih University, Faculty of Medicine, Ankara, Turkey
1 To whom correspondence should be addressed. e-mail: ilknurinegol{at}yahoo.com
Dear Sir,
We read with interest the article titled Antiphospholipid antibodies (APA) and recurrent pregnancy loss: treating a unique APA positive population. (Franklin and Kutteh, 2002). In this succesfully prospective cohort evaluation, authors also assessed the efficacy of heparin and aspirin therapy compared with aspirin alone in an APA-positive population (Franklin et al., 2002
).
A few questions have arisen. In this study, for APA positive pregnant women, the authors suggested the treatment with unfractioned heparin (UFH). For counteracting the osteoporotic effects of heparin, supplementation of calcium carbonate to achieve a total intake of 1.5g/day was prescribed for all patients (Dahlman et al., 1994). Were bone density measurements performed on patients before pregnancy and after treatment with heparin? If so, were there any differences on bone density measurements of patients? And the authors also stated that none of the patients had thrombocytopoenia. Which cut-off value was taken for thrombocytopoenia?
In a study of 16 pregnant women who received low molecular weight heparin (LMWH) for 1932 weeks, there was no significant change in mean bone density measurement from baseline measurements to the conclusion of therapy at 6 weeks postpartum and no patient experienced a decrease in bone mass of >10% at 6 weeks postpartum (Casele and Laifer, 2000). In a study of 34 women who received dalteparin, however, one woman without other risk factors for osteoporosis developed osteoporotic vertebral collapse postpartum. It was noted, however, that this patient had received higher than usual maintenance doses of LMWH (Hunt et al., 1997
). The risks of osteoporosis and thrombocytopoenia are lower in pregnant women treated with LMWH than in women treated with UFH (Melissari et al., 1992
; Sanson et al., 1999
).
Comparing with UFH, LMWH has more clinical and practical advantages. However, prospective, randomized controlled trials comparing LWMHs with UFH have not been performed. And due to Eldor (Eldor, 2001), it is hard to envisage that such clinical trials will be conducted, as most physicians are convinced of the efficacy of LMWHs and would be reluctant to use UFH during pregnancy because of the inconvenience and significant side-effects.
References
Casele, H.L. and Laifer, S.A. (2000) Prospective evaluation of bone density in pregnant women receiving the low molecular weight heparin enoxaparin sodium. J. Matern. Fetal Med., 9, 122125.[Medline]
Dahlman, T., Sjöberg, H.E. and Ringertz, H. (1994) Bone mineral density during long-term prophylaxis with heparin in pregnancy. Am. J. Obstet. Gynecol., 170, 12131220.[ISI][Medline]
Eldor, A. (2001) Thrombophilia, thrombosis and pregnancy. Thromb. Haemost., 86, 104111.[ISI][Medline]
Franklin, R.D. and Kutteh, W.H. (2002) Antiphospholipid antibodies (APA) and recurrent pregnancy loss: treating a unique APA positive population. Hum. Reprod., 17, 29812985.
Hunt, B.J., Doughty, H.A., Majumdar, G., Copplestone, A., Kerslake, S., Buchanan, N., Huhes, G. and Khamashta, M. (1997) Thromboprophylaxis with low molecular weight heparin (fragmin) in high risk pregnancies. Thromb. Haemost., 77, 3943.[ISI][Medline]
Melissari, E., Parker, C.J., Wilson, N.V., Monte,G., Kanthou, C., Pemberton, K.D., Nicolaides, K.H., Barret, J.J. and Kakkar, V.V. (1992) Use of low molecular weight heparin in pregnancy. Thromb. Haemost., 68, 652656.[ISI][Medline]
Sanson, B.J., Lensing, A.W., Prins, M.H., Ginsberg, J.S. Barkagan, Z.S., Lavenne-Pardonge, E., Brenner, B., Dulitzky, M., Nielsen, J.D., Boda, Z., Turi, S., MacGillavry, M.R., Hamulyak, K., Theunissen, I.M., Hunt, B.J. and Buller, H.R. (1999) Safety of low molecular weight heparin in pregnancy: a systematic review. Thromb. Haemost., 81, 668672.[ISI][Medline]