Signal that tells when labour about to begin

A cellular signal can tell doctors that a woman is about to go into labour, according to a study led by an Indian-origin scientist in the US. Researchers from the University of Texas Medical Branch (UTMB) at Galveston uncovered the cellular signal in the amniotic fluid around the foetus that builds up when a pregnant woman is about to go into labour.

"The initiation of the birth process is complex. Several body systems maintain pregnancy through a delicate balance -- altering this balance tends to promote labour," said lead author Ramkumar Menon, assistant professor in UTMB department of obstetrics and gynecology.

Menon's team focused their investigation on telomeres, which are the parts of the DNA that protect our genetic data while cells are dividing. These telomeres become shorter every time a cell divides, which hinders their ability to ensure that the new cells are identical to the parent cells.

This process is linked with the changes that take place in our bodies as we age. Over time, the telomeres become too short for the cell to divide and they become "senescent". "We investigated whether the presence of senescent telomere fragments in the amniotic fluid around the foetus is linked with labour status, as we know that the telomeres continue to get shorter as the pregnancy progresses," Menon said.

Menon's team wanted to know what triggered a change in the delicate balance that had maintained a pregnancy. "We began this study suspecting that the senescent cells cause oxidative stress-associated damages to the amniotic sac that create inflammation in the placenta," he said.

"We know from previous studies that inflammation can alter the balance of the mother's hormones in the uterus, triggering the labor process." The researchers used telomere mimics, resembling those found in amniotic fluid, and conducted cellular analyses, finding more telomere fragments when a woman who was in labour compared to women who were at the end of their pregnancy but not yet in labour.

They report that as the foetus mature in the womb and nears term, placenta and other related tissues also age correspondingly due to telomere fragmentation and eventual loss. The telomere fragments can increase sterile inflammation, as Menon termed, potentially signalling foetal maturity to trigger the process of labour and eventual delivery. (The findings were recently published in journal PLOS ONE.)