Experts at the University of Manchester reviewed studies and information around delayed villous maturation (DVM), in which some of the ‘villi’ in the placenta - tiny finger-like structures that allow nutrients and gases to pass from mother to baby – stop developing as they should towards the end of pregnancy.
Previous studies have found an association between DVM and stillbirth, with one appearing to show DVM is 4 times more likely to be found in the placenta after stillbirth than after a live birth.
However, DVM can only be diagnosed by examining the placenta after pregnancy. Scientists who carry out these tests use their own judgement to decide if DVM is present, so there are question marks over the reliability and consistency of findings.
The researchers say: “One of the biggest barriers to increasing understanding of DVM is the lack of a clear definition for diagnosis.”
“This highlights the need for a standardised set of criteria that can differentiate DVM from normal healthy placentas, and potentially even between different forms of villous immaturity.”
Women and birthing people with gestational diabetes are known to be more likely to experience DVM, and it’s thought there may be a connection with some other maternal conditions, such as polycystic ovary syndrome (PCOS). Higher rates of DVM are also associated with health problems that can affect babies in the womb, including gastroschisis (a defect in the abdominal wall) and congenital heart disease.
Because DVM cannot be detected during pregnancy, the only way to manage the risk is to monitor pregnant women and birthing people who are known to have been affected by the problem previously. This might involve closer screening for gestational diabetes and closely monitoring fetal movement during the third trimester.
But the researchers say that as DVM only recurs in some cases, intervening in every case where a woman or birthing person has been affected previously is ‘excessive’.
They conclude: “Ideally, an increase in knowledge of the pathogenesis of DVM could also help inform more robust management and treatment strategies.”
The research was funded by Tommy’s in partnership with The Ness Fund, set up in memory of baby Ness, who died at 38 weeks of pregnancy and who was found to have been affected by DVM.
Professor Alex Heazell, Director of Tommy’s Maternal and Fetal Health Research Centre in Manchester and one of the authors of the paper, said:
“This review clearly shows the need for more research into DVM. As a first step, we must agree how to define DVM so we can identify it accurately and consistently. That will allow us to measure its impact more precisely and pave the way for more effective treatment and prevention.”
Dr Jyotsna Vohra, Director of Research, Programmes and Impact at Tommy’s, said:
“Our goal at Tommy’s is to make pregnancy and birth safe for everyone, and to end the devastation caused by baby loss.
“To make progress, we need clear and robust evidence about the factors that may contribute to stillbirth.
“We welcome this review and hope it will act as a springboard for further research into the connection between DVM and stillbirth.”
