They also found deficiency of the vitamin was associated with greater weight and length but lower bone mass relative to body weight.
Further studies are needed to find out whether taking supplements or fortified infant formula to improve levels of the vitamin would help the build-up of bone mass, said the team from the University of Manitoba in Canada.
Vitamin D is required for normal bone growth and mineralization and deficiency can lead to rickets and increased risk of osteoporosis. Low levels of the vitamin have also been linked to multiple sclerosis and some forms of cancer, including breast and colorectal cancers.
The researchers measured blood levels of the vitamin D marker 25-hydroxyvitamin D in 50 healthy mothers and their newborn infants.
In the infants, anthropometry and lumbar, femur and whole-body bone mineral content were measured within 15 days of delivery. Mothers completed a 24-hour recall and three-day food and supplement record.
Twenty-three (46 per cent) of the mothers and 18 (36 per cent) of the infants had a plasma 25(OH)D concentration consistent with deficiency, report the scientists in the March 15 issue of the Canadian Medical Association Journal (vol 172, issue 6).
Infants who were vitamin D deficient were larger at birth and follow-up. Absolute lumbar spine, femur and whole-body BMC were not different between infants with adequate vitamin D and those who were deficient, despite larger body size in the latter group.
But in further analysis, higher whole-body bone mineral content was associated with greater gestational age and weight at birth as well as higher infant plasma levels of vitamin D.
It is not yet known whether long-term vitamin D deficiency may affect the growth of children and rates of osteoporosis later in life, however there is increasing evidence of a deficiency in this vitamin to the extent that rickets is making an alarming comeback.
In a commentary published in the same journal, Dr Leanne Ward, a pediatric endocrinologist at the Children's Hospital of Eastern Ontario in Ottawa, said that vitamin D deficiency among Canadian mother-infant pairs "is a persistent problem, despite existing recommendations for its prevention and despite ready access to vitamin D supplementation".
She said newborns who are being breastfed should receive a daily supplement of 400 IU of vitamin D, and if they live above the 55th parallel, that dose should increase to 800 IU in the winter months.
While breast milk is undeniably the best fluid for babies, it tends not to be rich in vitamin D.