Higher risk of preterm delivery for women born preterm

Women who were born preterm have a higher risk of giving birth to preterm children, according to a study, published in the journal Obstetrics & Gynecology, from researchers of the CHU Sainte-Justine and the University of Montreal. The researchers demonstrated that 13% of women born before 37 weeks of gestation gave birth prematurely at least once, compared to 9.5% of women born at term. Interestingly, this figure increased to 14% in women born before 32 weeks. "The difference is not alarming considering that according to our findings the vast majority of women born preterm gave birth at term. But it is significant enough to consider preterm birth a risk factor in monitoring pregnancies," said the senior author Dr. Anne Monique Nuyt.


Until now, it was known that low birth weight increased the risk of preterm delivery. But what about babies whose weights are low but still normal for preemies born at this age? "Our findings are unequivocal. The simple fact of being born prematurely increases the risk of premature delivery," said Ariane Boivin, lead author of the study. She explained that, to get a clear picture, the research team isolated the factor "born preterm" from the factor "birth weight for gestational age." To do this, they analyzed data from a cohort of 7,405 Quebec women who were born preterm over a period of 19 years, from 1976 to 1995, and compared it to that of women born at term.

"Knowing that being born preterm is a risk factor for expectant mothers, obstetricians could inform their patients of the warning signs of premature labour, so they can be vigilant and respond quickly if contractions occur," said Dr. Nuyt. The perspective of prematurity prevention is also among the benefits raised by the researcher. "Including preterm birth in the risk factors for pregnancy would also help to better target women most at risk when a preventive treatment becomes available," she added. Some of her colleagues at CHU Sainte-Justine are also working on developing drugs to prevent prematurity and thereby allow the fetus to continue to develop normally in the womb. "Having established with certainty a link between preterm birth and preterm delivery encourages us to continue our work to better understand the underlying biological and genetic mechanisms, in order to develop treatments that could one day prevent premature labour from occurring," she concluded.

About the study

The article "Risk for Preterm and Very Preterm Delivery in Women Who Were Born Preterm" was published online in the journal Obstetrics and Gynecology on April 7, 2015. The authors highlight the collaboration of the Institut de la statistique du Québec in collecting and analyzing the data. Anne Monique Nuyt is a neonatologist at CHU Sainte-Justine, researcher and head of the Fetomaternal and Neonatal Pathologies research axis at the CHU Saint-Justine Research Center, and professor at the Department of Pediatrics, University of Montreal. Ariane Boivin conducted this research study as part of her postdoctoral work under the supervision of Dr. Nuyt. The University of Montreal is officially known as Université de Montréal.


Maude Hoffmann

Communications, CHU Sainte-Justine Research Center

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