A new study from the University of Maryland reports that knowing which bacteria lurk in the mother’s cervix, as well as whether she possesses a particular type of immune factor, could hold the key to telling doctors how likely she is to enter premature labor, and in turn allow them to take preventive measures.
Shutterstock | Mircea Moira
This amazing conclusion allows researchers to work out an effective method to selectively fight the bacteria that predispose or trigger preterm birth, while sparing or encouraging the protective natural flora of the cervix.
Spontaneous preterm birth is one of the leading causes of death in infancy all over the world, including the USA. By definition, this is when the baby is born at less than 37 completed weeks of pregnancy.
The chief contributor to these deaths is the immaturity of multiple body systems leading to a host of potentially disabling complications in the newborn. These include respiratory difficulty, infections and metabolic aberrations.
Apart from infant deaths, these complications result in survivors with serious medical disorders such as cerebral palsy, loss of vision, and mental disability, which require lifelong care and enormous health-related expenditure.
While the caregiving burden is immense, the economic burden is no less formidable. The National Academy of Sciences puts the expenditure in this sector at $26 billion, in the USA alone.
Yet, the difficulty of understanding what causes spontaneous preterm birth has so far prevented the development of any reliable risk prediction or preventive measures.
The current study was distinguished by its multidisciplinary nature, which produced new insights into this complex clinical condition.
Here, 2,000 pregnant women were tested at three distinct points in pregnancy, using vaginal swabs to collect samples of bacteria and immune factors from their cervices. No previous study of the microbiome of the cervix and vagina in pregnant women has ever involved such a large number of women.
Novel modeling techniques generated a clear picture of the cervicovaginal microbiome. This showed that there were seven bacterial species whose presence signaled an increased risk of preterm birth. The effect was stronger in African-American women.
At the same time, the study revealed that the risk associated with these organisms fell in inverse proportion to the level of peptide β-defensin-2, which is an antimicrobial molecule that plays a part in innate immunity. This association was also dependent upon the ethnicity of the woman.
University of Maryland School of Medicine (UMSOM) Dean E. Albert Reese comments that this throws light upon one reason for the known disparity between white and African-American women in terms of preterm birth rate.
Predicting prematurity has been a riddle that has troubled researchers and clinicians for years, but we are finally shedding light on a path toward offering treatment to women we can identify as being at risk. Previous studies, including ours, were limited by low sample size. In establishing this large cohort, we aim to identify factors early in pregnancy that could be used to predict the risk to spontaneous preterm birth,"
Jacques Ravel, co-senior author
These results could lead to the evolution of accurate diagnostic tests for women at high risk of preterm birth. They also suggest new interventional therapeutics for this difficult condition, such as immunomodulatory drugs, and probiotics, or other measures to manipulate the microbiome of the cervix and vagina.
This study involved specialists in obstetrics as well as microbiology, and came from the University of Maryland’s School of Medicine, in collaboration with the Perelman School of Medicine at the University of Pennsylvania. It was published on March 21, in the journal Nature Communications.