Scientists discover muscular 'switch' that controls birth contractions

Date: Jun-19-2014In a world first, researchers in Australia have discovered an electrical switch in the

uterus that does not seem to work properly in overweight pregnant women and may help explain the

high rates of cesarean delivery in this group.

The study, led by Helena Parkington, an associate professor in the Faculty of Medicine,

Nursing & Health Sciences at Monash University in Melbourne, is published in the journal

Nature Communications.

After examining muscle biopsies taken from the uterus of 70 women, the team found an ion

channel that sends electrical signals and controls contractions of the uterus.

Prof. Parkington says the switch needs to be turned off for birth contractions to begin, but in

overweight women it appears to remain turned on, as she explains:

"The reason it stays on is that the 'molecular hand' that should turn the switch off fails to

appear in sufficient quantities in the uterine muscle of overweight women when labor should be

occurring."

In their study paper, the researchers describe how the ion channel - a potassium channel called

hERG - suppresses contractions before labor. The 'molecular hand' is an inhibitory protein that is

markedly enhanced during labor, "resulting in reduced hERG activity that is associated with an

increased duration of uterine action potentials and contractions."

Overweight women have low levels of protein that turns the switch off

They note that changes in channel activity contribute to "electrophysiological mechanisms" that

produce contractions during labor. In their study, they showed this system fails in overweight

women, whose hERG channel remains active as a result of low levels of the inhibitory protein.

The researchers say it may be possible to develop a drug that acts like the molecular hand, turning the switch on so labor and birth can progress normally.

The team believes the discovery significantly improves our understanding of how labor and birth

progress, and why women have complicated labors. It should be possible now to develop safe,

effective and specific treatments to correct the problem.

For example, it should be possible to develop a drug that acts like the molecular hand and

turns the switch on so labor and birth can progress normally.

Overweight pregnant women often go over their due date or have a slow labor once it

begins. They also need more medical help with labor and birth and have higher

rates of birth induction and cesarean section - due to failure to progress in labor.

Medical News Today recently reported a study led by Imperial College

London that showed how high maternal

BMI is linked to poor pregnancy outcomes. The study found that even small increases in

maternal BMI were linked to a higher risk of fetal death, stillbirth, neonatal death, perinatal

death and infant death.

Written by Catharine Paddock PhD

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Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.