Study Links Stress in Pregnancy, Lineage Genetics, and Preterm Birth

Scientists studying animal models suggest that stress in the lives of our mothers and grandmothers play a role in preterm births.

"We show that stress across generations becomes powerful enough to shorten pregnancy length in rats and induce hallmark features of human preterm birth,” said Gerlinde Metz, senior author of an article on the findings published recently online in BMC Medicine. “A surprising finding was that mild to moderate stress during pregnancy had a compounding effect across generations. Thus, the effects of stress grew larger with each generation."

Pertinent Points

- In studying rats, researchers found epigenetic changes that occurred when the mother was exposed to stress in pregnancy.

- Stress exposure, throughout several generations of rats, shorted the gestational period.

- These findings begin to establish the link between maternal stress exposure and preterm birth.

While the research is far from establishing the relationship in humans, the study authors believe that further investigation may provide better mechanisms for predicting and preventing preterm births. There may also be implications outside of prenatal care because they show that complex disease may be rooted in the experiences of prior generations.

To that end, the authors were able to identify epigenetic changes in non-coding RNA molecules (microRNA) that play a role in regulating gene expression. The researchers documented that when rats were exposed to stress during pregnancy, they could generate microRNA modifications, with effects across three generations.

The study focused on exposure to stress during pregnancy and the effects on subsequent generations of pregnant daughters. To understand the mechanisms that generated the changes in microRNA and to determine how the changes are passed on through generations requires further research, the authors said.

Besides noting the epigenetic changes and the shortened gestational period, the researchers also reported that exposure to stress in pregnancy also impacted maternal weight gain and behavioral activity, as well as increased blood glucose levels in the mother. Finally, stress increased placental miR-181a, which is a marker of human preterm birth.