Voluntary exercise in pregnant rats improves post-lactation maternal bone parameters but does not affect offspring outcomes in early life.

OBJECTIVES: The objectives of this study were to examine the effects of voluntary exercise during pregnancy on maternal post-lactation bone parameters and offspring growth. METHODS: Pregnant Wistar rats were housed in conventional cages (control), or were housed in raised cages requiring them to rise to an erect, bipedal stance to obtain food/water, throughout pregnancy. Dual energy X-ray absorptiometry and peripheral quantitative computed tomography scans were performed pre-mating and post-weaning. Maternal stress was assessed by fecal corticosterone measurement. Offspring weights were assessed at postnatal days 1 and 25 (weaning). RESULTS: Changes in bone mineral over the pregnancy/lactation period were site-specific. Exercise did not affect loss of bone mineral from the lumbar spine, but did attenuate the loss of trabecular bone mineral from the tibial metaphysis and enhance the strength strain index and cross-sectional moment of inertia at the tibial diaphysis (P≤0.05) in dams in the exercised group. Fecal corticosterone did not differ between dam groups. There were no significant differences in offspring weight between the exercised and control group at either time point. CONCLUSIONS: Voluntary exercise in the pregnant rat can improve some post-lactation bone parameters and does not adversely affect early postnatal outcomes of the offspring.