Aim: Emerging evidence indicates that mice conceived by in-vitro fertilisation (IVF) may be at risk of developing obesity, cardiovascular disease and type 2 diabetes. However, it is unclear whether these effects are due to the in vitro culture of the early embryo or ovarian hyperstimulation. Further the effects of high fat diet (HFD) on these differentially conceived offspring has not been examined. The study aims to metabolically phenotype adult mice conceived by IVF versus natural conception (NC) versus ovarian stimulation only (OS) following chow and HFD conditions.

Methods: C57Bl6/J mice were conceived by natural mating (NC group), by ovarian hormonal stimulation followed by mating (OS group) or by ovarian stimulation followed by fertilization and embryo culture (IVF group). Blastocysts generated by each method were transferred to the uteri of CBA F1 surrogate mice. Pups were weaned at 3-weeks of age before being placed on chow diet or HFD (60%fat) for 8 weeks. Body weights were measured weekly from birth. Intraperitoneal glucose tolerance tests (2g/kg) were performed at 11 weeks of age.

Results: There were no differences in litter size between groups. Birth weight of IVF mice (males 1.51±0.03g; females 1.52±0.03g) and OS mice (males 1.51±0.02g; females 1.54±0.03g) was lower than NC mice (males 1.68±0.03g; females 1.69±0.04g) (p<0.01). IVF females gained more weight than OS females (p<0.05), but there was no difference from NC females. High fat fed IVF and OS females had increased glucose area under the curve compared with NC females fed HFD (p<0.05). There was no discernible difference in glucose tolerance between groups on chow.

Conclusion: Preliminary data suggest that embryos conceived by IVF or hormone stimulation alone may exhibit impaired glucose tolerance as adults when exposed to high fat diet. Further studies to determine metabolic risks of IVF offspring are warranted.