Getting some space: Infants' and caregivers' containment and support spatial constructions during play.

Using a cross-sectional design, we examined the containment and support spatial constructions infants spontaneously create and those they observe when playing with a nesting toy. Infants (N=76) of 8, 13, or 18months played alone for 2min and then played with a caregiver for another 2min. At 8months, infants created few relations; at 13months, they inserted objects, resulting in containment, and stacked objects, resulting in support; at 18months, they created more than three times more containment relations than support relations, a result replicated in a second study. In contrast, caregivers created more support relations than containment relations, regardless of infant age, but labeled containment more than support. The results highlight differential exposure to containment and support in infant solitary and dyadic play. By 18months, infants gain greater firsthand experience with containment, a relation that is further reinforced by caregiver labeling.

Impact of Vitamin D Supplementation on Gross Motor Development of Healthy Term Infants: A Randomized Dose-Response Trial.

UNLABELLED: In addition to benefits for bone health, vitamin D is implicated in muscle function in children and adults. AIMS: To determine if vitamin D dosage positively correlated with gross motor development at 3 and 6 months of age. We hypothesized that higher doses would be associated with higher scores for gross motor skills. METHODS: A consecutive sample of 55 healthy, term, and breastfed infants from Montreal, Canada were recruited from a randomized trial of vitamin D supplementation between 2009 and 2012. Infants were randomized to 400 International Units (IU) (n = 19), 800 IU (n = 18) or 1,200 IU (n = 18) vitamin D3/day. Motor performance at 3 and 6 months was quantified by the Alberta Infant Motor Scale (AIMS). Plasma vitamin D3 metabolites were measured by tandem mass spectrometry. RESULTS: AIMS scores did not differ at 3 months. However, total AIMS scores and sitting subscores were significantly higher at 6 months in infants receiving 400 IU/day compared to 800 IU/day and 1,200 IU/day groups (p < .05). There were weak negative correlations with length and C-3 epimer of 25(OH)D. CONCLUSIONS: In contrast to our hypothesis, gross motor achievements were significantly higher in infants receiving 400 IU/day vitamin D. Our findings also support longer infants being slightly delayed.