Women may be more likely to give birth prematurely if they have low levels of the hormone progesterone, according to research.
These women could be identified through a number of examinations including a simple saliva test, researchers at University College and King’s College London said.
Progesterone helps women carry a baby to term because it stops the womb from contracting. Supplements can be used to help boost levels of the hormone.
The study, published in BJOG: An International Journal of Obstetrics & Gynaecology, found that women who gave birth prematurely, at around 34 weeks’ gestation, had lower levels of progesterone than those who carried their baby to term (37 weeks).
Around 7% of pregnancies in developed countries end in premature birth and the risks are higher for multiple - such as twin and triplet - pregnancies and for women over the age of 35.
Saliva samples of 28 women who gave birth before 37 weeks and 64 who delivered at term were analysed as part of the research.