Boston, MA – Researchers at Brigham and Women’s Hospital and colleagues at Children’s Hospital of Boston have found that specific types of bacteria that colonize the placenta during pregnancy could prevent illness or predispose to illness associated with preterm birth. These findings are published in the current issue of the online journal mBio®.
“Systemic inflammation initiated during pregnancy appears to contribute to morbidity and complications, underlying lifetime health challenges facing children born before term,” say Raina Fichorova and Andrew Onderdonk, leading authors of this study. “Our data suggest that placental colonization by specific groups of organisms can increase or decrease the risk of a systemic inflammatory condition of the newborn.”
Preterm birth occurs in nearly a half million pregnancies in the United States alone. Despite improved care, preterm and especially extremely low-gestational-age newborns continue to be at a considerably higher risk of morbidity, mortality and developmental problems. Much of this risk is attributable to imbalanced inflammatory responses of the fetus and newborn which scientists are now suggesting might be preventable by controlling the maternal microflora.
The systemic fetal inflammatory response to intrauterine exposures, especially intrauterine infections, is regarded as an important contributor to the onset and often lifelong consequences of preterm labor, fetal injury and early organ damage. Approximately half of all placentas delivered before the second trimester and 41% of those delivered by Caesarean section harbor microorganisms detectable by culture techniques.
In order to better understand what role these microorganisms could play in the extremely preterm inflammatory response, Dr. Fichorova’s Laboratory at the Brigham and Women’s Hospital Department of Obstetrics, Gynecology and Reproductive Biology analyzed protein biomarkers in dry blood spots obtained from 527 newborns delivered by Caesarean section. The Laboratory of Dr. Onderdonk at Brigham and Women’s Hospital Department of Pathology cultured and identified the bacteria from their respective placentas.
Placentas colonized primarily by microorganisms commonly associated with the condition known as bacterial vaginosis (BV) were found to be associated with elevated levels of proinflammatory protein in newborns. In contrast, colonization by Lactobacillus species of bacteria (often found in decreased concentrations during BV) were associated with lower levels of proinflammatory proteins.
“Our study supports the concept that the placental colonization with vaginal microorganisms can induce a systemic inflammatory response in the fetus and newborn and that the dominating molecular feature of this response can be dependent on the type of bacteria,” says Andrew Onderdonk. “Our data suggest that the targeting of placental colonization by specific drugs or probiotics during early pregnancy may hold promise for preventing not only preterm birth but also the devastating and far-reaching inflammatory consequences in premature newborns.”
For the full manuscript of:
Fichorova RN, Onderdonk AB, Yamamoto H, Delaney ML, DuBois AM, Allred EN, Leviton A, for the Extremely Low Gestation Age Newborns (ELGAN) Study Investigators. Maternal Microbe-Specific Modulation of Inflammatory Response in Extremely Low Gestational Age Newborns. mBIO 2011;2:e00280-10.