Embryo transfer in days 2 to 4 following intracytoplasmic sperm injection: a prospective cohort study

BACKGROUND Improvement of assisted reproductive technique (ART) results in higher pregnancy rates from positive Beta HCG to take home baby statistics. Despite developments in culture media allowing blastocyst stage transfer, some centers apply second, third and sometimes fourth day post injection for embryo transfer. This study aimed to compare their reproductive outcomes. METHODS This prospective cohort study conducted on 218 infertile couples with at least 4 oocytes retrieved and 2 good quality embryos. They were divided consecutively into 2nd (ET2) or 3rd (ET3) day embryo transfer. Some patients experienced 4rd (ET4) day embryo transfer due to weekend reasons, so we included them in our comparison as well. There were 98, 97 and 23 patients in the aforementioned groups, respectively. Reproductive and pregnancy outcomes were evaluated by Chi square and t-test with the significance level set at α=0.05. RESULTS Totally, 73 patients (33%) had positive beta HCG and 39.7 percent of them (n=29) experienced pregnancy loss. Positive Beta HCG was detected in 31(31.6%) of ET2 patients, 38 (39.2%) of ET3 patients and 4 (17.4%) of ET4 group. Abortion or pregnancy loss was reported in 9 (29%) of ET2 patients, 18 (47.4%) of ET3 patients and 2 (50%) of ET4 group. CONCLUSION Our study demonstrated that there may be a higher pregnancy as well as higher abortion in day 3 embryo transfer.