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.

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.

Insulin-like growth factors-I and -II and insulin-like growth factor binding protein-1 during normal pregnancy: pattern of secretion and correlation with other placental hormones.

OBJECTIVES: To describe pattern of secretion of insulin-like growth factor (IGF)-I, IGF-II, IGF binding protein (IGFBP)-1 and their correlation with each other and major placental hormones during normal pregnancy. DESIGN: Longitudinal study. SETTING: Academic Institutions and a Tertiary Care Maternity Hospital. PARTICIPANTS: Healthy women with singleton uncomplicated pregnancies (N = 35). MEASUREMENTS: Serum levels of IGF-I, IGF-II, IGFBP-1, chorionic gonadotrophin (HCG), placental lactogen (HPL), prolactin, oestradiol and progesterone were studied thrice during the antenatal period and within 24 h of delivery. RESULTS: IGF-I, IGFBP-1, HPL, prolactin, oestradiol and progesterone increased and HCG decreased significantly with advancing gestation (Repeated measures ANOVA: P < 0.01 to 0.0001). IGF-II levels were not significantly affected by period of gestation. Significant negative correlations (multiple regression analysis) were seen between IGFBP-1 and prolactin at 28 +/- 2 (P = 0.0226) and 36 +/- 2 (P = 0.0417) weeks of amenorrhoea (WOA) and between oestradiol and IGF-II at 36 +/- 2 WOA (P = 0.037). Prolactin and IGF-I at 14 +/- 2 WOA (P = 0.0225) and progesterone and IGFBP-1 at 28 +/- 2 WOA (P = 0.0216) correlated positively. CONCLUSIONS: Maternal IGF-I and IGFBP-1 but not IGF-II significantly increase as pregnancy advances. Components of the IGF system regulate or are affected by some of the placental hormones and the effects vary with the period of gestation.