Researchers have long been searching for the exact molecular triggers that lead a woman to go into labor, and a biochemical team from University of Texas Southwestern Medical Center in Dallas has now found it. The study was published yesterday in the journal Nature.
If you want the cliffs notes version, well…this isn’t the story for you. Labor turns out to be a hugely complex chain of events. The good news is that uncovering the exact process means researchers are now thinking of ways to develop treatments to prevent labor before a baby is ready — the “holy grail” of preterm labor research.
This is really important news. Here’s what they found:
The key is that tiny micro-fragments of RNA (DNA’s single-stranded cousin) in the uterus become extra active at the end of pregnancy. As circulating progesterone levels fall, these miRNA pieces are expressed strongly.
The miRNA affect two important genes (ZEB1 and ZEB2). These two genes keep labor at bay, because they keep levels of contraction-inducing hormones, like oxytocin, down.
Rising miRNA block the two genes, letting oxytocin loose, and labor beings.
Doctors and researchers know that infections and inflammation cause women to go into labor early. So they tested this on mice, inducing labor in some with an infection and others with hormones. Sure enough, the cascade of miRNA and ZEB genes held up.
This is a surprise to scientists, because the ZEB genes weren’t thought to be involved in labor at all – a scientific curveball. Now they know that when a woman gets an infection, these genes and the miRNA kick off contractions.
Now that they know the molecular pathway to labor, the Texas team will start looking for ways to suppress the action of the miRNA — with an eye toward therapies that could hold off pre-term labor.