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Single-stranded suture threads could prevent pregnancy infection complications, finds C-STICH trial

Women at risk of pregnancy loss who need a specialist surgical procedure are at a lower risk of infection if the procedure is carried out using a single-stranded suture thread, results from the C-STICH clinical trial found.

The trial was the largest of its type and is published in the Lancet. It involved more than 2,000 expectant mothers who needed a procedure called a cerclage, where a purse string suture is placed around the cervix (the neck of the womb) during pregnancy. Women were randomly allocated to have the surgical procedure performed using either a single-stranded thread or a braided thread.

Researchers tested whether there would be any difference in miscarriage or stillbirth, due to an increased risk of infection, from using a braided suture thread. The research, funded by the NIHR, demonstrated that single-stranded sutures could potentially improve outcomes for mothers at risk of preterm birth.

The team led by researchers from Birmingham Women’s and Children’s Hospitals (BWC) and the University of Birmingham – both founder-members of BHP – found that the mothers treated with single-stranded threads had no differences in pregnancy loss or preterm birth but reported fewer instances of infection and sepsis. This could have important implications for the health outcomes of mothers and babies who are treated with a cervical cerclage in their pregnancy.

Dr Vicky Hodgetts-Morton, NIHR Clinical Lecturer in Obstetrics at the University of Birmingham and Birmingham Women’s Hospital explained the implications of the trial results. Dr Hodgetts-Morton said:

“Preterm birth is a significant problem, complicating approximately one in ten pregnancies around the world. The consequences of preterm birth may be significant with some babies being born too early to survive, and those that survive are at increased risk of health complications. One cause for preterm birth is cervical insufficiency, occurring in 0.5% to 1% of pregnant women for which the placement of a vaginal cervical cerclage can be an effective treatment.

“Suture thread choice has the potential to improve how well a cerclage works in preventing miscarriage, stillbirth and preterm birth. Both single stranded and braided threads are commonly used to perform cerclages and our findings show no differences in pregnancy loss and preterm birth. The C-STICH trial results did show an increased risk of infections in labour and around the time of delivery with braided threads and this supported our hypothesis that a single stranded thread could reduce the risk of infection developing during the pregnancy.”

Mr Philip Toozs-Hobson, Chief Investigator of the C-STICH project and Consultant Gynaecologist at the Birmingham Women’s Hospital said:

“We are extremely grateful to all the women who trusted us by taking part in the study and also the dedication of the research teams at of the 72 maternity units who made the trial happen. Our aim, as ever, is to improve women’s experience in pregnancy through safer childbirth and to help the NHS achieve their target of reducing both pre-term birth and cerebral palsy. This work has added to our understanding relating to infection and sepsis.”

The study also highlighted that while single stranded suture threads led to better outcomes around infection, clinicians mentioned that such suture threads were subjectively more difficult to remove and more often required surgery to help remove under a general anaesthetic.