Correlation between umbilical cord concentration of the growth hormone‐IGF axis and small for gestational age: A single‐center retrospective, observational study

Objective To ascertain the association between small for gestational age (SGA) and growth hormone (GH)‐insulin‐like growth factor (IGF) system status. Methods This retrospective, observational single‐center study at a tertiary hospital classified 175 newborns into two groups based on their gestational age and birth weight: SGA ( n = 87) or appropriate for gestational age (AGA; n = 88). Umbilical cord blood samples were collected during delivery, and GH, IGF‐1, and IGF‐binding protein‐3 (IGFBP‐3) levels were measured using electrochemiluminescence immunoassay, liquid chromatography–tandem mass spectrometry, and chemiluminescence immunoassay, respectively. Results Compared with the AGA group, the GH concentration was significantly higher in the SGA group and the IGF‐1 concentration was significantly lower; there was no significant difference in the IGFBP‐3 concentration between the two groups. Gestational age, cesarean section, pre‐pregnancy maternal body mass index (BMI), weight gain during pregnancy, gestational hypothyroidism, and IGF‐1 concentration had a significantly positive association with neonatal birth weight. After adjusting for maternal age, gestational age, fetal sex, mode of delivery, pre‐pregnancy BMI, gestational weight gain, gestational hypertension, gestational hypothyroidism, and gestational diabetes, elevated GH levels and decreased IGF‐1 levels were both significantly associated with an increased risk of SGA, but there was no association with IGFBP‐3. Conclusions Levels of IGF‐1 and GH in the GH‐IGF system are associated with SGA. Elevated GH levels and decreased IGF‐1 levels both increase the incidence of SGA. Imbalance in the GH‐IGF‐1 axis may restrict fetal growth and development, thereby increasing the risk of future metabolic diseases.