Vitamin Information Center

NEW YORK (Reuters Health) - Softening of the skull bones in normal-appearing newborns is tied to a vitamin D deficiency in the womb, according to Japanese researchers.

They suggest that breast-fed infants with this condition may need vitamin D supplements.

Soft skull bones, also known as craniotabes, in normal newborns is usually regarded as no cause for alarm, but Dr. Tohru Yorifuji at Kyoto University Hospital and colleagues dispute this in their report in the Journal of Clinical Endocrinology and Metabolism. They point to evidence that the condition is associated with type 1 diabetes, reduced bone mass during childhood, and lowered immunity.

In their study, the researchers screened 1120 normal infants at 5 to 7 days of age. Craniotabes was considered present when “the skull bones reversibly bended by application of pressure by the examiner’s fingers.”

They found that 246 babies, or 22 percent, had craniotabes. The highest rate occurred among infants born in April and May, and the lowest in those born in November.

Vitamin D production in the body is triggered by sunlight, and Yorifuji’s team points out that the rate of craniotabes “was influenced by the daylight hours approximately 4 months prior to delivery.” They say this strongly suggests that “the condition is associated with vitamin D deficiency in utero.”

Low vitamin D levels and other abnormalities at 1 month of age were more common in babies who were breast-fed than in those who were fed formula at least part of the time, the investigators found.

They therefore recommend “treating breast-fed infants with craniotabes with vitamin D, or preferably, treating all pregnant women with vitamin D.”

SOURCE: Journal of Clinical Endocrinology and Metabolism, online February 12, 2008.

BABIES are healthier if their mothers are pregnant with them over summer, according to research.

Researchers said babies with softer skulls were more likely to have been in the womb over winter - because their mothers lacked enough vitamin D, which is absorbed from sunlight.

Dr Tohru Yorifuji from the Kyoto University Hospital said his team’s study of more than 1100 newborns in Japanese hospitals revealed that pregnancies over winter could lead to problems in babies.

“Craniotabes, the softening of skull bones, in otherwise normal newborns has largely been regarded as a physiological condition without the need for treatment,” Dr Yorifuji said.

“Our findings, however, show that this untreated condition may be the result of a potentially dangerous vitamin D deficiency.”

In an article to be published in the May edition of the Journal of Clinical Endocrinology & Metabolism, the researchers said 22 per cent of babies studied had craniotabes.

“The incidence was highest in (babies) born in April-May and lowest in those born in November,” the researchers said.

“Otherwise, the incidence of craniotabes was not significantly related with the maternal age, number of pregnancies, birth weight, or weeks of pregnancies.”

Dr Yorifuji said mothers should also be concerned about how much vitamin D their baby needed while feeding.

“Until more research is done on the effects of perinatal vitamin D deficiency, we suggest treating breast-fed infants with craniotabes with vitamin D, or preferably, treating all pregnant women with vitamin D.”

A lack of vitamin D in adults has previously been linked to increased risks of multiple sclerosis, type 1 diabetes and other diseases.