Children born to mothers with low levels of vitamin D during pregnancy are twice as likely to have severe language problems when they are at school, Perth researchers have found. The Telethon Institute for Child Health Research study is the first to show low levels of the vitamin in utero can harm a child\'s language development, including the ability to pick up new words and string together sentences. The research, published in the international journal Pediatrics, monitored more than 740 pregnant women, with follow-up investigation of their child\'s development and behaviour up to age 17. A quarter of the women had insufficient vitamin D levels while pregnant. Associate Professor Andrew Whitehouse, who led the research, said the finding was significant, given vitamin D levels in women were known to have decreased steadily over the past 20 years. \"The developing baby is completely reliant on the mother for its vitamin D levels and what we have shown is that this might have an impact on the child\'s brain development,\" Dr Whitehouse said. \"We\'ve known for some years that vitamin D insufficiency during pregnancy in mums is associated with a number of adverse health effects, including poor growth of the baby and asthma, but no human studies have shown an association with language difficulties. These are more severe language problems in school years, because while we know 12 per cent of toddlers have language delays, many of them resolve by the time they get to school, whereas language problems which persist to school years tend to stick around for much of their life.\" Dr Whitehouse said the findings could help provide an early intervention to prevent some language difficulties. But more research was needed to fully understand the impact of vitamin D levels on the developing brain. There was no suggestion pregnant women should spend more time out in the sun to get vitamin D. \"We would now like to explore whether vitamin D supplements in pregnancy could reduce the risk of language problems for children,\" Dr Whitehouse said. The study found no link between vitamin D levels and childhood behaviour and emotional problems.