IRISHWOMEN who are pregnant during the summer are more likely to have a baby with longer thigh bones, according to new research.
The baby benefits from the the greater share of sunlight which boosts the mother's vitamin D levels, the findings published in 'Fertility and Sterility' revealed.
"While inside the womb, the developing baby is entirely dependent upon the maternal pool of vitamin D, which is critical for the normal development of the baby's bones," says study author, Fionnuala McAuliffe, Professor of Obstetrics and Gynaecology at the UCD School of Medicine and Medical Science in UCD and Holles Street Hospital Dublin.
The study looked at 60 caucasian pregnant women in Ireland. Thirty of the women, from the winter group, had their pregnancy during the winter months and delivered in March and April.
The other 30, known as the summer group, had their pregnancy during the summer months and delivered in September and October.
"We identified a link between the mother's and baby's vitamin D level and the length of the baby's thigh bone at 20 weeks, at 34 weeks, and the baby's length at birth," said Prof McAuliffe.
"The women with lowest vitamin D levels in early pregnancy (the winter group) had babies with slightly shorter thigh bones than those born from mothers with normal vitamin D levels (the summer group)," she added.
The study by researchers from University College Dublin and the National Maternity Hospital, Ireland, funded by Health Research Board, measured the vitamin D levels in the mothers' blood in early pregnancy and at 28 weeks. The cord blood vitamin D value was also measured, which reflects the baby's vitamin D level.
Deficiencies in vitamin D during pregnancy can lead to reduced bone growth in babies before birth and poor bone development in early childhood.
Dr Jennifer Walsh, one of the researchers involved in the study, suggested vitamin D supplements should be considered for pregnant women in Ireland and in other northern countries with poor dietary intakes of vitamin D, and in particular for women who will go through their early pregnancy during the winter months.