RESUMO
PROBLEM: We aimed to investigate the main causes of recurrent miscarriage (RM) in patients with losses after spontaneous gestation (SG) and after in vitro fertilization (IVF). METHOD OF STUDY: A prospective case-control study was conducted. The eligible patients were women who had experienced two or more consecutive abortions after <12 weeks' gestation, two consecutive losses after SG, or two consecutive losses after IVF. All patients were subjected to the following evaluations: karyotyping of the aborted material, alloimmune and autoimmune marker testing, and acquired and hereditary thrombophilia marker testing. RESULTS: In total, 58 patients were eligible: 32 patients with RM after SG and 26 patients with RM after IVF. The factors associated with RM were genetic (29%), immune (14%), thrombophilic (21%), and thrombophilic and immune (24%), and only 12% of the cases were idiopathic. Comparing the two study groups (SG and IVF), all studied factors were similar, except for a higher ANA positivity observed in the SG group (SG 30.4% vs IVF 5.3%, OR 8.6 (CI 1.1-21.1, P .048). CONCLUSION: Our study identified the possibly factors associated with recurrent miscarriage in 86% of the cases, and these factors appear to be similar in patients with recurrent miscarriage after spontaneous gestation and IVF. This study demonstrates that IVF with PGT-A with euploid embryo transfer could reduce abortions by up to 29%, but other factors need to be investigated even in patients undergoing in vitro fertilization.