A simple dental treatment may reduce a woman's risk of giving birth prematurely, research suggests.
Dental treatment could cut the risk of babies being born early
A study published in the Journal of Periodontology showed treating severe gum disease with scaling and root care cut premature births by 84%.
It was known that having a dental disease increased the risk of giving birth early.
The said all women who are pregnant, or thinking of having a baby, should have a dental check-up.
Around 40,000 babies are born prematurely, before 37 weeks gestation, in the UK each year, putting them at increased risk of conditions such as cerebral palsy, lung and gastrointestinal problems, vision and hearing loss and even death.
Doctors have already established that severe gum infections cause an increase in the production of prostaglandin and tumour necrosis factor, chemicals which induce labour, to be produced.
In this study, researchers assessed 366 pregnant women who had periodontitis, a serious gum infection.
They were either given the scaling and root planing dental treatment alone, an antibiotic, both the treatment and the drug or the treatment and a dummy pill.
In scaling and root planing, both the tooth and root surfaces are cleaned to remove plaque and tartar and bacteria.
Those who received the dental treatment before the 35th week of pregnancy had a reduced risk of giving birth prematurely.
But being given adjunctive metronidazole therapy, an antibiotic used to treat infections, did not reduce their risk.
And those women given the antibiotic after scaling and root planing had more premature births than those who were given the treatment and a dummy pill.
Professor Marjorie Jeffcoat, of the University of Alabama at Birmingham school of dentistry, who led the research, said: "What this tells us is that scaling and root planing may significantly reduce a mother's chance of having a preterm birth.
"We found no evidence that the addition of an antibiotic to scaling and root planing was of benefit in this study.
"However, more research needs to be conducted to determine the reason for the decrease in efficacy."
She added; "In light of these findings, I recommend that all women who are thinking of becoming pregnant or who are pregnant receive a full periodontal exam and diagnosis.
"Women who are already pregnant when periodontal disease is detected are ideally treated with scaling and root planing in the second trimester."
A spokeswoman for Bliss, the premature baby charity, told BBC News Online: "Earlier research has certainly suggested an association between gum disease in pregnant women and an increased risk of premature birth.
"Any new research that looks at ways of reducing the risk of premature birth, which can have such a traumatic effect on the baby and its parents, is welcomed and should be taken note of.
"However before parents hopes are raised, Bliss considers that more research is needed to study the relationship between periodontal disease and premature birth."