New Zealand women and babies are at high risk of vitamin D deficiency, and the risk is even greater for those living in the South Island, researchers say.
Research from the University of Otago shows that woman and their babies are at a greater risk of vitamin D deficiency and that current health guidelines fall short of curbing this trend.
The study recruited 126 woman from Dunedin's Queen Mary Maternity Centre from 2011 to 2013.
The findings, published in the journal Nutrients, found vitamin D deficiency rates were "very high", evident in 65 percent of mothers and 76 percent of infants.
There was also evidence of rickets in three infants.
Lead author Dr Ben Wheeler, from Dunedin School of Medicine's Department of Women's and Children Health, says the study raised "significant questions" around current public health policies for those living in Southern New Zealand.
"Current policy does not appear effective at preventing vitamin D deficiency and its consequences.
"This is particularly an issue in New Zealand as living further south potentially decreases one's ability to make vitamin D and the country has negligible vitamin D fortification," he says.
Present public health policy is to only consider vitamin D supplementation for pregnant women and breastfed infants who are considered "at risk" if they have naturally dark skin, complete sun avoidance, a sibling with rickets, liver or kidney disease, or taking medications that affect vitamin D levels and infants who are breastfed over winter.
Dr Wheeler says strengthening of current New Zealand guidelines is needed.
"Further consideration should also be given to offering a fully funded universal supplement to New Zealand women and their children during pregnancy and lactation, particularly those in the South Island."
Maternal vitamin D status during pregnancy is influenced by a range of factors, including season, skin colour, supplementation, latitude, and potential pregnancy-specific variations in metabolism.
Supplementation studies during pregnancy demonstrate significantly improved infant status at birth and beyond.
Vitamin D is essential for foetal bone health, growth, and dental health. A lack of vitamin D is also associated with an increased risk of rickets in childhood.