Possible cause of preterm births found: study

Scientists have found that small calcium deposits in foetal membranes lead to a mother's water breaking early - solving the mystery behind why some babies are born prematurely.
The study suggests that dietary or other interventions may prevent those preterm births.
Researchers from US Nationwide Children's Hospital found that in preterm, premature rupture of the foetal membranes - that is, water breaking significantly early- the amniotic sac contains calcium deposits and early markers of bone formation.
The membranes, then, are less elastic and more prone to breaking.
"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," said Irina Buhimschi from Nationwide Children's Hospital

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

The study also demonstrates how the deposits occur. Many human body fluids, including saliva and blood, can produce calciprotein particles. When those particles deposit in soft tissues outside of the skeleton, they can lead to harmful calcification.
Calciprotein particles have been implicated in kidney stones, atherosclerosis and aneurism rupture. A protein called fetuin-A helps prevent those particles from depositing where they should not.
This study shows for the first time that amniotic fluid can also produce calciprotein particles.

In cases of preterm premature rupture of membranes, the amniotic fluid has decreased concentrations of fetuin-A, resulting in a decreased ability to stop the particles from depositing in the amniotic sac.
When researchers exposed foetal membrane cells to calciprotein particles, the particles led the foetal membrane tissue to begin creating osteoblasts, the precursors of bone.
These findings suggest that it may be possible to identify pregnancies at greater risk for premature preterm rupture of membranes, said Buhimschi. They also suggest possible interventions to prevent these kinds of preterm births.
"We need to see if there are women who lack the capacity to prevent these early calcifications. I also believe strongly that there are dietary measures that would improve the intra-amniotic environment for these women," Buhimschi added.

The study was published in the journal Science Translational Medicine.