Nicotinamide, a component of complex culture media, inhibits mouse embryo development in vitro and reduces subsequent developmental potential after transfer.

Objective: To determine the effects of B-group vitamins present in culture media on mouse embryo development in vitro and subsequent viability.

Design: Mouse zygotes were cultured in the presence of B-group vitamins. Embryo morphology and cell numbers were determined at 96 and 120 hours after hCG. Viability was assessed by transfer of embryos after 3 days of culture to pseudopregnant recipients. Resultant pregnancy rates (PRs) and fetal weights were determined.

Results: Supplementation of an amino acid-free medium with minimal essential medium (MEM) B-group vitamins significantly decreased embryo cleavage rates, whereas the inclusion of Ham's F-10 medium B-group vitamins significantly reduced both cleavage rates and morphological development. Subsequent experiments determined that nicotinamide (5 microM) significantly reduced blastocyst cell number, implantation rate, viable PR, and fetal weight.

Conclusion: The data indicate that nicotinamide inhibits mouse embryo development in culture and reduces viability. Nicotinamide is present at high levels in Ham's F-10 and MEM media that are used routinely in human embryo culture. The role of vitamins in human embryo development in vitro warrants investigation.