根據一項最新研究發現，口腔中的細菌能夠出現在子宮中，導致子宮感染從而引起早產。

在美國Case Western保留地大學(Cleveland, Ohio, USA)研究人員開展的研究中，從19例因為早產或者高危早產而接受跨腹膜檢查的孕婦中，收集了羊誰、血液、陰道拭子和口腔拭子標本。使用PCR和核酸測序方法檢測了這些樣本的細菌DNA。

在所有14例被檢測患者的口腔中發現了一種尚未被命名的細菌，但是只有一例子宮感染的羊水中發現了這種細菌。該患者隨后由于感染而分娩，在懷孕24周就分娩了嬰兒。對她胎盤的檢查結果發現了嚴重而彌散的絨膜羊膜炎和胎兒血管炎，累及了臍帶和胎盤，這被推測這是導致早產的原因。但是在陰道拭子中沒有發現推測可能出現的細菌。該結果證實了一些科學家的懷疑：宮內感染并不總是來自生殖道“上行”的細菌，同樣可以來自口腔“下行”的細菌。該研究結果發表在2006年4月的《臨床微生物學》期刊之上。
 
Oral Bacteria May Cause Uterine Infections
 
Bacteria in the mouth may find their way to the uterus, causing uterine infections that can lead to preterm birth in pregnant women, according to a new study.

In a study by researchers at Case Western Reserve University (Cleveland, Ohio, USA), amniotic fluid, blood samples, vaginal swabs, and oral swabs were collected from 19 pregnant women who were undergoing transabdominal amniocentesis because of preterm labor or threatened preterm labor. The samples were analyzed for bacterial DNA via polymerase chain reaction (PCR) and nucleotide sequencing.

An as yet unnamed species of the bacterium genus Bergeyella was detected in the mouths of all 14 women tested, but in the amniotic fluid of only one patient with a uterine infection. That patient subsequently went into labor, induced by the infection, and delivered her baby at 24 weeks' gestation. Analysis of her placenta revealed severe and diffused chorioamnionitis and fetal vasculitis involving the umbilical cord and chorionic plate, which were the presumed cause of her preterm labor. However, the bacterium was not detected in the vaginal swab, as might be expected. The finding confirmed what some scientists have suspected: that intrauterine infections don't always "ascend" from the genital tract but can "descend" from the oral cavity. The study was published in the April 2006

issue of the Journal of Clinical Microbiology.