The Joint Annual Scientific Meetings of the Endocrine Society of Australia and the Society for Reproductive Biology 2018

Maternal glucose tolerance and pregnancy outcomes in sheep exposed to a simulated shift work protocol   (#80)

Tamara Varcoe 1 , Kathryn Gatford 1 , Hong Liu 2 , David Kennaway 1
  1. Robinson Institute, University of Adelaide, Adelaide, South Australia, Australia
  2. University of Adelaide, Adelaide, SA, Australia

Epidemiological studies have suggested a small but significantly increased risk of miscarriage, preterm birth and fetal growth restriction when working night or rotating shift schedules during pregnancy. Shift workers are also at increased risk of developing type 2 diabetes and obesity, however the impact during pregnancy on maternal metabolic homeostasis is unknown. This study assessed the impact of simulated shift work exposure during pregnancy on maternal glucose tolerance and pregnancy outcomes in sheep. Following estrus synchronisation, 65 merino ewes were naturally mated then group housed in light controlled sheds. Ewes were randomly allocated to a control photoperiod (12h light: 12h dark), or to simulated shift work conditions whereby the timing of light exposure and food presentation was reversed twice each week throughout pregnancy. At week 7 and 19 of gestation, ewes were subjected to intravenous glucose tolerance test (0.25 g/kg). Simulated shift work exposure during pregnancy impaired glucose tolerance and increased glucose stimulated insulin secretion at week 7 but not week 19 of gestation. Gestation length was greater in simulated shift work exposed ewes with twin fetuses (+2.4 days, P=0.024). There was a treatment x litter size interaction effect on birth weight, with evidence of fetal growth restriction in singleton fetuses exposed to simulated shift work (-478g, P=0.016). These results have implications for the large number of Australian women currently engaged in shift work, and further studies are underway to determine the impact upon progeny health.