The relation between saliva estriol levels in pregnancy and infant birth weight.

Specimens of saliva were obtained from 106 women with normal pregnancies and from 42 women, whose children turned out to small for dates (birthweight below the 10th centile). Saliva estriol was highly significantly (P less than 0.0001) decreased in the group with a newborn with a birthweight below the 10th centile (500 +/- 340 ng/ml, mean +/- SD) when compared with the group with infants whose birthweight was over the 10th centile (813 +/- 449 ng/ml). Estriol determination in saliva seems to be a simple, non invasive method of aiding the detection of fetal growth retardation.