Role of total antioxidant capacity in the differential growth of human embryos in vitro

Objective: The objective of this study was to examine the relationship of early human embryonic development parameters with day 1 culture media total antioxidant levels (day 1 TAC). Design: Prospective study. Setting: Patients undergoing assisted reproduction (ART) in a teaching hospital. Patient(s): Patients undergoing conventional IVF (n = 153; 167 cycles) and intracytoplasmic sperm injection (ICSI; n = 105; 116 cycles) were included. Both fertilization and early cultures were performed in human tubal fluid (HTF) with 5% serum substitute supplement. Intervention(s): Levels of total antioxidants in the central well (sample) and the outer well (control) of each embryo culture dish were measured. Main Outcome Measure(s): Fertilization rate and embryo quality at days 3 and 5 were recorded for each cycle. Age, parity, and demographic features were also compared. Result(s): After controlling for all demographic and clinical variables, day 1 TAC was related to fertilization rates in both groups of patients. Day 1 TTC was significantly related to high (> 7) day 3 cell number, low (< 10%) fragmentation rate, and blastocyst development rate in both conventional IVF and ICSI cycles. Day 1 TAC was related to pregnancy in ICSI but not conventional IVF cycles. Conclusion(s): Day 1 TAC appears to be an important biochemical marker for early embryonic growth. Decreased embryonic fragmentation, enhanced cleavage rate, and increased blastocyst development rate may be partially related to day 1 TAC in the culture media. Whether this relationship is a cause or effect needs further assessment.