Etiological evaluation of repeated biochemical pregnancy in infertile couples who have undergone in vitro fertilization

Objective This study aims to investigate whether there are any notable etiologies for repeated biochemical pregnancy (RBP) and, if so, to compare those etiologies associated with repeated spontaneous abortion in infertile couples who have undergone in vitro fertilization (IVF). Methods Forty-four infertile couples who underwent IVF and experienced RBP were included in this study. RBP was defined as more than 2 early pregnancy losses that occurred before the detection of a gestational sac, with ectopic pregnancies specifically excluded by serial serum beta human chorionic gonadotropin evaluation. Forty-three infertile couples who underwent IVF and experienced recurrent spontaneous abortion (RSA) were included as a control group. Karyotype analysis, anatomic evaluation of uterus, endocrine and immunological evaluation were performed. In addition, the number of pregnant women confirmed by 12 weeks' gestation was compared between groups. Results Immunological factors (RSA: 20.9% vs. RBP: 29.5%, P=0.361), diminished ovarian reserve (RSA: 10.9% vs. RBP: 17%, P=0.552), and parental chromosomal abnormalities (RSA: 18.6% vs. RBP: 9.1%, P=0.218) were not different between groups. Additionally, the incidence of uterine factors (RSA: 11.6% vs. RBP: 4.6%, P=0.206), unknown cause (RSA: 48.8% vs. RBP: 54.5%, P=0.161), and the pregnancy outcome identified until 12 weeks' gestation (RSA: 46.5% vs. RBP: 38.6%, P=0.520) did not differ between groups. Conclusion In the present study, the causes of RBP after IVF were similar to those of RSA. Accordingly, we suggest that efforts should be made to define the etiology of RBP, particularly for infertile couples, and that possible management strategies should be offered.