To the Editor:
We read with great interest the article by Jaslow et al. (1). They proposed to determine whether the frequency of abnormal results for evidence-based diagnostic tests differed among women with recurrent pregnancy loss (RPL) based on the number of prior losses (N = 2, 3, or >4).
We agree that it is a relevant clinical question, but first of all the correct inclusion criteria of pregnancy loss should be respected. In 2008, the American Society for Reproductive Medicine (ASRM) defined RPL by two or more failed pregnancies, and pregnancy must be clinical: documented by ultrasound or histopathologic examination (2) .
Unfortunately, the authors included patients with multiple positive urine βhCGs. Biochemical pregnancies (pregnancies documented only by a positive urine or serum hCG test) is a bias that compromise a considerable and growing proportion of RPL patients and is found in the majority of papers about this issue, as in the work from Jaslow et al.(1).
Some of the pregnancies included in these studies might be spontaneous reabsorbed ectopic pregnancies or very early implantation failures due to genetically abnormal embryos. The etiologies of recurrent biochemical pregnancies might be different from those of clinical pregnancy losses (3). Other common lifestyle factors (including obesity, occupation, history of alcohol use, and caffeine consumption), which are expected to modify the outcome, should be reported when studying RPL (3, 4). The retrospective data from Jaslow et al. recommend the evaluation of all couples with more than 2 consecutive pregnancy losses. Nonetheless, this recommendation could only be done based on results from prospective trials with rigorous RPL inclusion criteria.
Finally, until adequate trials in diagnosis and treatment of RPL are published, clinicians should avoid indicating precocious investigation tests and empirical treatments. Couples should, on the other hand, be provided with honest evidence-based information: be informed that the majority of cases remains unexplained despite investigation (60% according to Jaslow et al.) and that couples with 3 or 4 RPL have a 75% chance for a successful future pregnancy if offered supportive “love” care (5).
Helena von Eye Corleta, Ph.D., M.D.
Universidade Federal do Rio Grande do Sul and GERAR Nucleo de
Reprodução Humana do Hospital Moinhos de Vento
Porto Alegre, Brazil
1. Jaslow CR, Carney JL, Kutteh WH. Diagnostic factors identified in 1020 women with two versus three or more recurrent pregnancy losses. Fertil Steril 2010; 93:1234-43.
2. Definitions of infertility and recurrent pregnancy loss. Fertil Steril 2008; 90: S60.
3. Christiansen OB et al. Evidence-based investigations and treatments of recurrent pregnancy loss. Fertil Steril 2005; 83:821-39.
4. Jauniaux E et al. Evidence-based guidelines for the investigation and medical treatment of recurrent miscarriage. Hum Reprod 2006; 21:2216-22.
5. Clifford K, Rai R, Regan L. Future pregnancy outcome in unexplained recurrent first trimester miscarriage. Hum Reprod 1997; 12:387-9.
Published online in Fertility and Sterility doi:10.1016/j.fertnstert.2010.06.020