Background:There is a need to elucidate what affects the implantation and early pregnancy course in pregnancies conceived with assisted reproductive technology (ART) so that pregnancy rates and outcomes can be improved. Our aim was to determine the role of maternal Helicobacter pylori infection.Material and methods:We did a prospective study of 187 infertile couples undergoing intracytoplasmic sperm injection (ICSI) and segregated those according to underlying infertility etiology. We assessed the status of H. pylori IgG antibodies and anti-CagA IgG antibodies by ELISA assay. All pregnancies were followed for early pregnancy loss (EPL, first 12 weeks).Results:The likelihood of H. pylori infection increased with age (1.01, 95% confidence interval [CI]: 1.0–1.13; P = 0.040) but there was no association with EPL. Women infected with CagA-positive strains were more likely to have EPL (19.39, 95% CI: 1.8–208.4; P = 0.014). Women with tubal factor or ovulatory disorder infertility were more likely to abort early (12.95, 95% CI: 1.28–131.11; P = 0.030, 10.84, 95% CI: 1.47–80.03; P = 0.020, respectively). There was no association between EPL and age, number of embryos formed or transferred, or number of oocytes retrieved.Conclusion:Our findings suggest that infection with CagA-positive H. pylori strains is linked to an increase in women’s potential to abort early (possibly through increased release of inflammatory cytokines). In addition, tubal factor and ovulatory disorder infertility are linked to EPL after ICSI due to unknown mechanisms. Proposals to eradicate H. pylori infection prior to ICSI could lead to a decrease in EPL after ART.