Objective: To investigate the relationship between preterm delivery and maternal serum insulin-like growth factor-I (IGF-I) and insulin-like growth factor-binding protein-1 (IGFBP-1) levels.
Design: A study over a 12 month period in which all samples were collected according to a pre-set protocol.
Setting: St. Bartholomew's Hospital, London.
Subjects: Thirty-eight nonpregnant adult females, 456 pregnant women at various gestational ages, 84 women with average-for-gestational-age babies at term delivery, and 49 pregnant women with preterm delivery (44 with singleton pregnancy and five with twin pregnancy).
Main outcome measures: Serum IGF-I and IGFBP-1 levels were determined by radioimmunoassay.
Results: Serum IGF-I concentrations increased as pregnancy progressed. In the third trimester, serum IGF-I levels in singleton preterm deliveries were lower than those in normal pregnancies, and IGFBP-1 concentrations were higher than those in normal pregnancies. This phenomenon was not obvious in the second trimester. Maternal circulating IGFBP-1 levels were correlated inversely with birthweight in women with singleton preterm delivery.
Conclusions: Neither IGF-I nor IGFBP-1 appears to play a significant role in preterm delivery since maternal serum IGF-I and IGFBP-1 levels are similar in preterm and term deliveries.