A simple change in the way doctors try to prevent premature births could be a life-saving "game changer" for pregnant women and newborn babies worldwide.
When an expectant mother has a history of early labor and shows signs that her cervix is shortening and opening too soon, doctors will stitch the opening closed in an effort to delay delivery. The most commonly used stitching — braided sutures — with the procedure was associated with three times the risk of stillbirth and nearly twice the risk of preterm birth, compared to the less popular monofilament option, British researchers said Wednesday.
If doctors performing the procedure switched from a braided suturing material to a monofilament thread, "it would prevent 170,000 preterm births and 172,000 fetal losses” worldwide, said Dr. Lindsay Kindinger of the Imperial College in London and lead researcher.
A change in the microbiome
The researchers examined the medical records of 678 women whose cervixes had been sewn shut, a procedure known as cervical cerclage, to prevent preterm birth. With braided suturing material, the risk of stillbirth was higher (15 percent versus 5 percent) as was the risk of preterm birth (28 percent versus 17 percent).
To investigate the cause, the researchers followed a smaller group of women through their pregnancies, randomly assigning 25 to get braided sutures and 24 stitches with monofilament. After monitoring the vaginal environments throughout the women’s pregnancies, the researchers discovered that the microbiome had changed significantly in the women who got braided sutures.
The new study “could be a game changer,” said Dr. Siobhan Dolan, a professor of obstetrics and gynecology at the Albert Einstein College of Medicine and the Montefiore Medical Center and medical advisor to the March of Dimes.
“Preterm birth has dramatic short and long term outcomes for children,” Dolan said. “When you find something like this that is straight forward and easy to implement, it’s really a breakthrough.”
Leading cause of infant deaths
In 2014, preterm birth affected about one out of every 10 infants born in the United States, according to the Centers for Disease Control and Prevention. A baby is considered preterm when delivered before 37 weeks.
Preterm birth is the greatest contributor to infant death and the leading cause of long term neurological disabilities in children, according to the Centers for Disease Control and Prevention.
Kindinger suspects that stitches made with braided multifilament material are more likely than those made with monofilament material to disrupt the bacterial environment in the vagina, which could spark inflammation — one of the risk factors for preterm birth.
That makes sense, said Dr. Michal Elovitz, a professor of obstetrics and gynecology and director of the maternal and child health research program at the University of Pennsylvania School of Medicine.
“We’ve seen that changes in the bacterial community in the gut can have an impact on immunity,” said Elovitz, who is not affiliated with the new study. “It’s not surprising that the same sort of phenomenon could happen in the vaginal space.”
Since there doesn’t appear to be any evidence that the braided sutures are better than the microfilament stitches, it would make sense based on the current study to switch, Elovitz said.
A place for bacteria to grow
It shouldn’t be surprising that a braided suture might have a deleterious impact on vaginal bacteria, Dolan said.
“There was the same issue with IUDs back in the 60s and 70s," Dolan said. "The use of braided string led to an increase in pelvic inflammatory disease compared to IUDs with monofilament string. It’s possible that the braided string, with its little cracks and crevices, might provide a place for bacteria to grow.”
Dr. Hyagriv Simhan would like to see more research first.
“It’s an intriguing study,” said Simhan, a professor of obstetrics and gynecology at the University of Pittsburgh School of Medicine and division chief of maternal-fetal medicine at Magee-Womens Hospital at the University of Pittsburgh Medical Center. “But it should be followed up with studies that are designed to answer the question.”
Simhan would like randomized controlled studies in which women would be randomly assigned to receive each type of suture and then followed through their pregnancies to see if there was a difference in outcomes, based on the material used.
At this point, Simhan said, “I don’t think there should be a guidance to doctors saying you shouldn’t use braided sutures.”
The study was published in the journal Science Translational Medicine.