Washington, Nov 10 (IANS): A new US study, involving more than 100 pregnant women may have solved the mystery of why many babies are born prematurely.

The study published Wednesday in the US journal Science Translational Medicine pinpointed abnormal calcium deposits in the membranes surrounding the developing foetus as a potential culprit in premature birth, Xinhua news agency reported.

The deposits are early markers of bone formation, making the membranes less elastic and more prone to breaking significantly early, according to the study conducted by Ohio-based Nationwide Children's Hospital.

"We do see calcium deposits in full term births as well, which is probably part of the normal breakdown of the membranes at the appropriate time," Irina Buhimschi, Director of the Center for Perinatal Research at the hospital's Research Institute, said in a statement.

"The membranes are supposed to rupture when labour is underway. However, these calcium deposits are too many and too early," Buhimschi said.

Abnormal calcium deposits have been previously linked to kidney stones, atherosclerosis, and aneurism rupture.

The findings suggested that it may be possible to identify pregnancies at greater risk for premature rupture of membranes, said Buhimschi.

They also suggested possible interventions to prevent these kinds of pre-term births.

"I believe strongly that there are dietary measures that would improve the intra-amniotic environment for these women," she said.

"We know that dietary interventions are critical in atherosclerosis and other disease processes that involve calciprotein particles. We just have never considered it in pre-term premature rupture of membranes before," she added.