Paternal body mass index is associated with decreased blastocyst development and reduced live birth rates following assisted reproductive technology.

OBJECTIVE: To determine the relationship between paternal body mass index (BMI), embryo development and pregnancy, and live birth outcomes after assisted reproductive technology (ART). DESIGN: Retrospective analysis of ART cycles. SETTING: Major assisted reproduction center. PATIENT(S): Three hundred five couples undergoing ART in a private fertility clinic. INTERVENTION(S): No intervention was undertaken in patients involved in this study. MAIN OUTCOME MEASURE(S): Live birth outcomes and clinical pregnancy rates. RESULT(S): No significant relationship between paternal BMI and early embryo development was found. However, increased paternal BMI was associated with decreased blastocyst development, clinical pregnancy rates and live birth outcomes. CONCLUSION(S): To our knowledge, this is the first report linking increased paternal BMI and clinical pregnancy and live birth rates after ART treatment. Further work to elucidate the mechanisms involved is required.

Day 4 embryo selection is equal to Day 5 using a new embryo scoring system validated in single embryo transfers.

BACKGROUND: Single embryo transfers (SETs) require the most viable embryo from a cohort to be selected. Day 4 embryos may provide a selection advantage similar to blastocyst transfer as embryos are replaced post-embryonic genome activation and into the uterus where they would normally reside. However, there is currently no adequate morphological system to assess Day 4 embryos. Therefore, we developed an assessment system for Day 4 embryos and retrospectively assessed Day 4 SET success rates compared with Day 5 SETs. METHODS: Embryos (n = 996 after IVF or ICSI) were assessed on Day 4 of development, prior to implementing Day 4 embryo transfers, to obtain a descriptive range of embryo morphologies observed at this time point. A morphological scoring system was developed from this. All patients having an SET after extended culture (Day 4, n = 124 or Day 5, n = 193), at Repromed, Adelaide, Australia, during June 2006-January 2007 were analysed for pregnancy outcome. Ongoing pregnancy was determined by fetal cardiac activity at 6-8 weeks after oocyte collection. RESULTS: Day 4 and 5 SETs resulted in similar ongoing pregnancy rates of 38.7% and 32.1%, respectively. CONCLUSIONS: A Day 4 scoring system was successfully developed and implemented. Day 4 SETs were found to be a viable option or alternative to Day 5 SETs with no difference in pregnancy rates.