Long summer days result in longer bones

An Irish study of pregnant women has found that those with a summer pregnancy give birth to babies with longer thigh bones.

It is based on the human ability to produce vitamin D from exposure to UVB light, which stops during the months from November to March for those in northern latitude countries due to depleted sunshine.

The research, carried out at University College Dublin and the National Maternity Hospital, focused on two groups of 30 women who gave birth following pregnancies during summer and winter months respectively.

The Fertility and Sterility study found that those who gave birth after being pregnant in the winter time frame had children with shorter thigh bones.

“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 UCD.“The women with lowest vitamin D levels in early pregnancy had babies with slightly shorter thigh bones than those born from mothers with normal vitamin D levels .”