25 January 2010
Stillbirth linked directly to mother's oral bacteria
by Kate Melville
Confirming long-held suspicions, a Case Western Reserve University researcher has for the first time established a direct link between a mother's oral bacteria and the death of her fetus. Researcher Yiping Han's revelations about Fusobacterium nucleatum and its likely role in pre-term labor and stillbirths appear in the February issue of Obstetrics & Gynecology.
The mother in question carried the baby fullterm, but during the 35-year-old's pregnancy she reported excessive gum bleeding, a symptom of pregnancy-associated gingivitis. Around 75 percent of pregnant women experience gum bleeding due to the hormonal changes during pregnancy.
The bleeding associated with the gingivitis allowed the bacteria - normally contained to the mouth because of the body's defense system - to enter the blood and work its way to the placenta. Even though the amniotic fluid was not available for testing, Han suspects that the bacteria entered the immune-free amniotic fluid and eventually were ingested by the baby.
Han explained that normally a mother's immune system takes care of the bacteria in the blood before it reaches the placenta. But in this case, the mother also experienced an upper respiratory infection just a few days before the stillbirth. "The timing is important here because it fits the time frame of hematogenous [through the blood] spreading," Han said.
Postmortem microbial studies of the baby found the presence of F. nucleatum in the lungs and stomach. The baby had died from a septic infection and inflammation caused by bacteria. After questioning the mother about her health during the pregnancy, Han arranged for her to visit a periodontist, who collected plaque samples from her teeth.
Using DNA cloning technologies, Han found a match in the bacterium in the mother's mouth with the bacterium in the baby's infected lungs and stomach. "The testing strongly suggested the bacteria were delivered through the blood," Han said.
Happily, with preventative periodontal treatment and oral health care, the mother has now given birth to a healthy baby. Han suggests women who are considering a pregnancy seek dental care to take care of any oral health problems before conceiving.
Source: Case Western Reserve University