Maternal and cord blood levels of insulin-like growth factors--I and--II and insulin-like growth factor binding protein-1: correlation with birth weight and maternal anthropometric indices.

ABSTRACT

OBJECTIVES: To study the correlation of maternal and cord blood insulin like growth factor (IGF)-I and -II and IGF binding protein (IGFBP)-1 levels with birth weight and maternal anthropometric indices. DESIGN: Longitudinal prospective study. SETTING: Academic Institutions and a Tertiary Care Maternity Hospital. PARTICIPANTS: Women with uncomplicated singleton pregnancy (N = 35) and their newborns. MEASUREMENTS Maternal weight, height, symphysiofundal height and serum levels of IGF-I, IGF-II, IGFBP-1 were measured thrice during the antenatal period, within 24 h of delivery and at 6 weeks and 6 months postpartum. Newborn anthropometric indices were recorded at birth, and at 6 weeks and 6 months of age. Cord blood levels of IGF-1, IGF-II, IGFBP-1, paternal height and weight, and placental weight measured. RESULTS: Maternal and cord blood IGF-I levels were lower than values reported for Caucasians. All newborns showed adequate growth at birth, and up to 6 months of age. Cord blood IGF-1 positively correlated with chest circumference (r = 0.4532, P = 0.0262), IGFBP-1, negatively with birth weight (r = -0.4024, P = 0.0461) and IGF-II had no effect. Cord blood IGF-I positively correlated with maternal levels at 28 +/- 2 (r = 0.4571, P = 0.0247) and 36 +/- 2 (r = 0.4291, P = 0.0364) weeks of amenorrhoea, whereas IGF-II and IGFBP-1 did not correlate with maternal values. Maternal IGF-I, IGF-II and IGFBP-1 did not correlate with newborn or maternal anthropometric indices. Placental weight correlated significantly with birth weight (r = 0.5299, P = 0.0348) and head circumference (r = 0.5031, P = 0.0470). CONCLUSIONS: Cord blood IGFBP-1 and placental weight appear to be determinants of birth weight variation even among appropriately grown for gestational age newborns.