Researchers at the March of Dimes Prematurity Research Center at Imperial College London have developed a testing device that may help advance diagnosis and treatment of preterm birth. A study, published in Nature Communications, finds that the device can rapidly and accurately detect changes in vaginal bacteria and corresponding immune responses in pregnant women, which are associated with increased risk of preterm birth. This cost-effective test could facilitate faster clinical decision making and help improve targeted treatment strategies during pregnancy. 

Preterm birth remains a major cause of death worldwide in children under age five. One of the many factors that contribute to a woman’s risk of preterm birth is changes during pregnancy to the type and amounts of microbes in the lower reproductive tract, referred to as the vaginal microbiome. In some women, certain bacteria from the microbiome can cause inflammation leading to an increased risk of preterm birth. 

This new testing device called direct-on-swab metabolic profiling by desorption electrospray ionization mass spectrometry (DESI-MS), rapidly analyzes chemicals in a clinical swab to simultaneously determine the type of bacteria in the vagina, and corresponding immune or inflammatory response to the bacteria. This two-minute test was found to be just as effective as “gold standard” chemical profiling tests (e.g. liquid chromatography-mass spectrometry assays) that require detailed sample preparation and extraction making them more time consuming (up to eight hours per assay), costly and difficult to introduce into routine bedside testing. The ability to monitor the vaginal microbiome and inflammation throughout pregnancy with DESI-MS could help identify women at risk of preterm birth sooner, potentially allowing obstetricians to monitor these women more closely and start preventative treatments earlier and in a more targeted way than currently possible. 

“This test is groundbreaking for March of Dimes and an example of how our Prematurity Research Centers are working toward ending the preterm birth crisis for moms and babies, especially in communities of color, where a woman is twice as likely to give birth preterm,” says Stacey D. Stewart, president and CEO of March of Dimes. “Furthermore, this innovative test will be able to help empower pregnant women with information that supports a full term, healthy pregnancy.”

Imperial College London researchers tested the direct-on-swab DESI-MS device by analyzing more than 1,000 samples collected from two independent groups of pregnant women (about 400 women in total) in the United Kingdom. The data found that women who had changing and diverse vaginal microbiomes (those that contained many different bacteria or had bacteria that changed during pregnancy) had higher rates of preterm birth and were more likely to have increased inflammation. The test also detected inflammation caused by some treatments received during pregnancy (e.g. a stitch put into the cervix for “cervical cerclage” treatment). This inflammation was most frequently observed in women subsequently experiencing preterm birth.

The device may have broader application to other areas of women’s health where the vaginal microbiome has been implicated, including bacterial vaginosis, HIV and HPV infection, cervical dysplasia, IVF failure and miscarriage. Researchers now plan to register the technology and seek regulatory approval for its use in the U.K. and Europe and, eventually, in North America. They also are planning development of a miniature version of the test that can be used more widely in clinics and would allow for bedside testing.

“We’ve known for some time that the vaginal microbiome can contribute to the risk of preterm birth, but now we have developed a device which in just a few minutes can report both the microbiome composition and inflammatory status of a sample collected during pregnancy,” says David MacIntyre, PhD, reader in Reproductive Systems Medicine, Institute of Reproductive and Developmental Biology Department of Metabolism, Digestion, and Reproduction at Imperial College London. “This is the first rapid testing device of its kind and could be readily transferred to use in a clinical setting. This information could be used by doctors and patients to monitor risk of preterm birth but also to help optimize treatments, such as more selective use of antibiotics.”

Professor Phillip Bennett, MD, PhD, from the Department of Metabolism, Digestion and Reproduction at Imperial College London adds that “an unhealthy microbiome is an important cause of preterm birth that, currently, we have no way of diagnosing or treating. The introduction of this test into research studies, and into clinical practice should have a dramatic effect on our ability to prevent these preterm births, and could have wider applications in other areas such as miscarriage and prevention of cervical cancer.” 

March of Dimes, the infant and maternal health leader, is dedicated to advancing knowledge and solutions for preterm birth. It has five Prematurity Research Centers located in hospitals, medical centers and universities across the U.S. and London advancing this critical research. Each Prematurity Research Center pursues a set of research themes and their findings inform and amplify the work of the other centers. Additionally, their data are shared with the broader scientific community through a data repository to help move the entire field forward together. At Imperial College London, research is highlighting the important role of the reproductive tract microbiome in shaping preterm birth risk and other pregnancy outcomes.