Intracytoplasmic morphologically selected sperm injection and congenital birth defects: a retrospective cohort study

Our objective was to study the birth defect rates in intracytoplasmic morphologically selected sperm injection (IMSI) pregnancies. A cohort of couples presenting male factor infertility between January 2006 and January 2014 was retrospectively analyzed. Discharge letters and a telephone interview were performed for assessing pregnancy outcome. All clinical data were reviewed by a board certified medical geneticist. Main outcomes were fetal/birth defect and chromosomal abnormality rates. Two thousand two hundred and fifty-eight pregnancies were available for analysis, of them, 1669 (73.9%) resulting from ICSI and 2258 (26.1%) achieved by IMSI. Pregnancy outcome distribution did not show a significant difference. For the fresh embryo transfer cohort, fetal/birth defect rate was 4.5%, chromosomal aberration rate was 1.0%, and structural malformation rate was 3.5%. IMSI vs. ICSI pregnancies were less likely to involve a fetal/birth defect: 3.5% vs. 4.8%, respectively, but did not reach a statistical significance OR 0.71 (95% CI 0.39-1.22). Split by multiplicity, this trend existed only for singleton pregnancies; 1.4% structural malformations rate vs. 3.8%, respectively, OR 0.35 (95% CI 0.11-0.9). The frozen cohort demonstrated a significantly lower birth defect rate (OR 0.25, 95% CI 0.09-0.58). We conclude that IMSI procedure does not involve an increased malformation rate and may offer a reduced anomaly incidence. Further studies are required.