A SIMPLE saliva test could help identify which pregnant women are most at risk of going into premature labour, a British study has found.
Researchers at University College London and King’s College London found abnormally low levels of the hormone progesterone in the saliva of women going into early pre-term labour (before 34 weeks gestation).
Details of the exploratory study, published in the British Journal of Obstetrics and Gynaecology, indicated low levels of progesterone in their saliva as early as 24 weeks and that the levels failed to rise in the normal way during pregnancy.
Progesterone is produced in large quantities by the placenta during pregnancy and is thought to help stop the womb from contracting. A sharp drop in progesterone in the final stage of pregnancy is associated with the onset of labour.
The hormone is commonly given to women who are deemed at risk of pre-term labour but so far there are no reliable tests to predict which women will go into labour early.
Professor of obstetrics and gynaecology at National University of Ireland, Galway, John Morrison, said a test that would improve the ability of clinicians to predict premature birth would be a significant development.
But Prof Morrison said there had been a number of studies looking at various hormone levels in saliva during pregnancy and it remained to be seen whether this one would “bear good clinical results”.
“Traditionally the research has focused on measuring the levels of oestrogen in saliva and, while this hormone does predict pre-term birth, the test is not very reliable,” he said. The UK study appears to suggest progesterone may be a more reliable indicator, Prof Morrison said.
About 70,000 babies are born here every year and 5-7 per cent (3,500-5,000) are classified as premature births. But only about 30-40 per cent of pre-term births are a result of premature labour; most are due to complications in pregnancy which require medical intervention.
Low birth weight and pre-term birth are leading causes of infant mortality.
While giving progesterone appears to stop some women going into premature labour, it is not clear if the treatment lessens the risks associated with preterm birth for the baby.
