Early pregnancy loss in IVF: a literature review

Human reproduction is an imperfect process despite years of evolution. It is estimated that only 30% of conceived pregnancies end up with a live birth (Hum Reprod Update 8:333-343, 2002). Although the IVF cycle clinical pregnancy rate is estimated to be above 60%, the actual live birth rate is still well below 50% (Reprod Biomed Online 40:201-206, 2004). Errors of implantation, embryonic genetic mutations, structural as well as chromosomal abnormalities, endometrial aberrances as well as abnormal sites of implantation are all conditions that could be associated with a positive pregnancy test yet a non-viable pregnancy outcome. In this extensive literature review, we detailed the different risk factors hindering a successful reproductive outcome post-IVF in terms of early pregnancy loss. We also reviewed the different treatment modalities available to improve the prognosis of such patients.