Calcium crystals hold clues to preterm delivery

Calcium crystal deposits in the amniotic fluid may help to explain preterm premature rupture of the membranes (PPROM) and resulting early delivery in some pregnant women without another apparent cause.

“We noticed that in many women, analysis of the proteins in their amniotic fluid did not show signs of inflammation, and we could not find any cause for their preterm birth,” lead author Lydia Shook said. “We took a fresh look for what was causing breakdown of the membranes, which can lead to lost elasticity, integrity, and eventually rupture.”

Researchers at Yale University School of Medicine stained placental and fetal membrane tissue from women with preterm births caused by PPROM and women with full-term deliveries. They found calcium deposits containing fetuin, a major protein involved in nanoparticle formation, in fetal membranes collected from preterm deliveries. Calcifying nanoparticles play a role in degenerative conditions such as arthritis and atherosclerosis.

The researchers used a sterile culture technique to determine whether amniotic fluid can form nanoparticles, then exposed fetal membranes to the cultured nanoparticles to ascertain whether the nanoparticles could lead to cell dysfunction, damage, and death.

Women with PPROM had lower levels of fetuin in amniotic fluid than women who gave birth early with intact membranes. “Low fetuin may be a biomarker for women at risk of PPROM,” says Shook. “The goal of this research is to identify women at risk of developing the condition early in their pregnancy and to intervene with targeted therapy.”

Their findings were presented at the Society for Maternal-Fetal Medicine Scientific Sessions, San Francisco, on February 10.