The goal of this study was to verify if endocrine factors play some role in the determination of the birth weight in healthy term newborn infants. Patients included 21 LGA (mean BW= 3998g, 58% male, 50% vaginal delivery) and 39 AGA (mean BW= 3189g, 51% male, 71% vaginal delivery) infants of non-diabetic mothers with an uneventful prenatal care and without perinatal asphyxia or congenital malformations. Cord blood and 48-72 h. of life peripheral blood samples were drawn in order to perform the following tests: plasma glucose by glucose-oxydase method, serum insulin and proinsulin by immunofluorometry, and IGF I by radioimmunoassay.

Results are expressed in median (variation). Non-parametric tests were performed with rejection level of 0.05. Table

Table 1
Full size table

This study did not show significant association between plasma glucose, serum insulin and IGF I and birth weight, bud did show higher levels of serum proinsulin in LGA infants born of non-diabetic mothers.

Proinsulin could be a good beta pancreatic activity marker, and its level is directly proportional to birth weight.