Molecular Mechanism that Controls Labor Found

Researchers have found the molecular mechanism that triggers labor in women. The study also explains why obese women have high rates of Cesarean section deliveries.

According to University Of Melbourne scientists and colleagues, an electrical switch in normal weight women switches off at the end of pregnancy. This leads to the beginning of labor pains. However, in overweight or obese mums, this switch remains on, which leads to longer gestation time and the need for induced labor.

The study was based on uterine samples obtained from 70 pregnant women. The research team found a uterine muscle ion channel that is associated with uterus contractions. This channel, researchers said, functions poorly in obese mothers.

"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 labour should be occurring. These women also respond poorly to our current methods of induction," said Professor Helena Parkington of Monash University, who is the lead author of the study.

Previous research has shown that obese or overweight mothers have several complications throughout delivery. The present study explains why obese women have higher rates of C-section deliveries.

Knowing the reason behind labor onset could help researchers design better treatments for women with a complicated delivery, researchers said.

"The clinical significance of this discovery is that, having identified the problem responsible for dysfunctional labour in overweight women, we are now able to look at developing a safe, effective and specific treatment to correct the problem," said Shaun Brennecke from the University of Melbourne and Royal Women's Hospital. "For example, a drug to turn off the switch to allow normal labour to start and progress," he added.

A recent study had also found that C-sections take longer in overweight/obese mothers than in normal-weight women.

Around half of all pregnant women in the U.S. are overweight or obese. And, about eight percent of women falling in the reproductive age are extremely obese. Health experts say that maternal obesity increases health complications for both mother and child. Women planning pregnancy must consider attaining ideal weight before conceiving.