Preterm delivery: predictable by saliva

Women who give birth prematurely, before 34 weeks gestation, have saliva that has low levels of progesterone, a hormone involved in the menstrual cycle.

Women who give birth prematurely, before 34 weeks gestation, have saliva that has low levels of progesterone, a hormone involved in the menstrual cycle, according to a British study whose results were published Wednesday, July 22 at the site of the British Journal of Obstetrics and Gynaecology. This low rate, detectable as early as six months, could develop a simple, noninvasive to identify risks of premature delivery.

Researchers from University College and King's College London have collected saliva samples from 92 women. The latter all had a higher risk of premature delivery. They have also been recruited on this criterion: they have already experienced this type of delivery, or miscarriage. Extracts from saliva of these women have been collected since the 24th week of gestation until 34 weeks or until delivery, as appropriate.


Women are divided into different groups: those who delivered before 34 weeks' gestation, eight and a half months, those who gave birth between the 34th and 37th weeks, and those who delivered at term, after 37 weeks.

Women who delivered before 34 weeks gestation have a saliva with progesterone levels lower than those which gave birth to term, after 37 weeks. These results are confirmed for all the moments of pregnancy, from the 24th week.

The study authors point out that progesterone is known for its anti-inflammatory capabilities, and suggest that low levels of this hormone in the body of the mother may contribute to bacterial infection, a recognized cause of preterm delivery.

These tests could help predict preterm delivery, by collecting saliva of pregnant women.