202 Effect of mild chronic restraint stress on gestational weight gain in murine model

To assess the effect of restraint stress on gestational weight gain in a murine model. Nulliparous female mice, divided among C57BL/6 (n=14), DBA/2 (n=11), and B6D2F1/J (n=9) strains were bred at 8-10 weeks of age with B6D2F1/J males. Detection of a copulation plug was used to determine embryonic day (E) 0.5. Dams were then randomly assigned to either stress or control groups. The mice assigned to stress underwent daily 2-hour periods of restraint in a ventilated clear 50-mL conical centrifuge tube from E1.5-E15.5. The primary outcome was the difference between weight on day E15.5 compared to day E0.5. Pregnancy was confirmed by either preterm delivery from E15.5-E17.5 or by inspection of the uterus after sacrifice on E17.5. Mean weight gain for each strain was compared between the control and stress groups using independent sample t-tests. Values of p < .05 were considered statistically significant. Mean gestational weight gain is presented in Figure 1. DBA/2 and B6D2F1/J mice exposed to restraint stress demonstrated significantly lower gestational weight gain than their respective controls (p=.001 and p=.005, respectively). There was not a significant difference in gestational weight gain in stressed C57BL/6 mice compared to controls (p=.70). Mild chronic restraint stress results in decreased gestational weight gain in DBA/2 and B6D2F1/J mice but not in C57BL/6 mice.