Researchers discovered the existence of a biological timer that launches from the first days of pregnancy, which could be involved in premature childbirths.
- Researchers have discovered in mice a molecular timer that plays a role in controlling the moment of childbirth.
- This timer, which impacts the cells of the uterus, activates from the first days of pregnancy.
- If the same process is observed in humans, some premature births could be linked to events occurring at an early stage of pregnancy.
A standard pregnancy lasts between 40 and 41 weeks. However, some babies arrive earlier, even very early. Indeed, 10 % are born before 37 weeks of gestation. Many of these premature births remain quite mysterious.
Researchers from the University of California San Francisco made a major step forward while they studied mice. They discovered a “molecular timer” which activates from the first days of pregnancy.
Their work was presented in the journal CellJanuary 21, 2025.
Gestation time: KDM6B plays a role from the first days of pregnancy
The team decided to focus on a protein called KDM6B because they suspected that the latter plays a role in regulating genes involved in the transition to work.
By following pregnant mice, scientists noticed that when they blocked the protein, pregnancies became longer and the little ones were born later than usual. Additional analyzes have shown that the effects of KDM6B on the duration of the gestation were linked to cells called Fibroblasts. The latter play a role in regulating work. And, another important discovery: the protein studied controlled them from the first days of pregnancy.
“Our results highlight a surprising role of uterine fibroblasts in the regulation of the moment of childbirth”explains the researcher Tara McIntyre in a press release. “It was not something we had planned, and it completely reshaped our understanding of the types of cells and the processes that determine the triggering of work.”
A biological timer causing certain premature deliveries
Complementary experiences on pregnant mice revealed that shortly after design, methyl groups appear on histones (basic protein of the cell nucleus) near certain genes in uterine fibroblasts. These genes then remain inactive. This phenomenon helps the uterus to support pregnancy.
The researchers then noticed that the methylation levels of these histones decrease slowly and regularly during pregnancy. When the rates are low, the genes that regulate work can ultimately set out. “”Basically, what seems to happen is that this timer is triggered from the start of pregnancy, then slows down “specifies the main author Dr Adrian Erlebacher. “When the methylation of histones erodes enough, the neighboring genes are busy.”
“When the researchers blocked KDM6B, histones close to certain genes accumulated too much methylation at the start of pregnancy. This increased” threshold “meant that, despite erosion, these genes were not activated in time, Which delayed work “explain the authors.
They argue that the discovery of this “molecular timer” could help better understand and prevent premature births, if it is confirmed that the same process is present in humans. “”If the newly studied molecular signals are disturbed in humans, they could be linked to the risk of premature childbirth, the team estimates. For example, some women could start pregnancy with methylation levels of histones lower than normal. This could lead to methylation erosion and activate work -related genes too quickly. “
In addition, premature births could thus be explained by events that occur very early in pregnancy, and not only in the last weeks.
