We selected consenting mother-infant pairs (n = 408) who met our inclusion criteria (singleton pregnancy, no genetic abnormalities, and no preexisting diabetes) and for whom sufficient amniotic. We explored the possibility that perturbations in amniotic fluid glucose, insulin, and insulin-like growth factor-binding protein 1(IGFBP1) and/or metabolic acids exist before routine screening for GDM. These results show that 2nd trimester AF IGF BP1, BP3, and IGF II may emerge as early indicators of fetal growth.
Regression analyses revealed that AF IGF BP3 was positively associated with birth weight within LGA and macrosomia subpopulations (partial r2 = 0.0283 and 0.0404, respectively). Multivariate regression analysis that controlled for maternal height, prepregnancy weight, smoking behavior, infant gender, gestational age, parity, as well as amniocentesis week showed that higher AF IGF BP1 was associated with lower birth weight (partial r2 = 0.0062). Maternal and fetal characteristics were obtained from questionnaires and medical chart review. AF samples were collected after routine genetic testing (15.1 +/- 0.04 wk, range 12-20 wk) from 543 mother-infant pairs in Montreal, QC, Canada. Birth weights were categorized using recently developed birth-weight-for-gestational-age percentiles for fetal growth in which infants 90% as LGA (large-for-gestational-age). and its binding proteins IGF BP1 and 3, measured early in pregnancy, were associated with and predictive of infant birth weight. Our objectives were 2-fold: 1) to assess the concentration and distribution of insulin-like growth factor II (IGF II) and its binding proteins (BP) 1 and 3 in 2nd trimester amniotic fluid using ELISA, and 2) to establish whether concentrations of AF IGF II.
The developing fetus begins to swallow amniotic fluid (AF) early in gestation, a process that results in ingestion of numerous growth factors. Taken together, these data would suggest that AMF metabolites measured during routine amniocentesis might provide important early information about the in utero environment and metabolic maturity of the developing fetus, thus opening the future possibility of early diagnosis of low birth However, for each subclassification - normal, low birth weight or macrosomic infants - not all AMF constituents predicted growth and development. After controlling for the established predictors of birth weight (gestational age, maternal height and prepregnancy weight, and smoking behavior), multiple regressionsÄemonstrated that AMF glucose, lactate and IGF 2 were positive predictors of infant birth weight at term, while IGFBP-1 and betahydroxybutyric acid were negative predictors of infant birth weight. We measured AMF glucose, insulin, insulin-like growth factors (IGFs) and their binding proteins (IGFBP 1&3) and lactic, uric and keto-acids in AMF samples collected at 14-16 wks gestation from women >35yrs (n> 500) undergoing routine amniocentesis for genetic testing in Montreal, Canada. Therefore our objective was to establish if metabolic constituents in AMF could predict infant birth weight. Amniotic fluid (AMF) serves both as a repository of metabolic wastes and as a nutrient source during fetal growth. Low birth weight (4000g, is estimated at 9-10%.