Correlation of gestational age with maternal human chorionic somatomammotropin and maternal and fetal growth hormone plasma concentrations during labor

Abstract

The effect of gestational age on the interrelationships between infant weight (n = 464) and maternal (n = 331) and cord (n = 464) growth hormone (GH) concentrations and maternal (n = 326) human chorionic somatomammotropin (HCS) levels was determined in unselected obstetric patients delivered of infants between 31 and 45 weeks of gestation. A significant negative correlation (r = −0.113) was observed between gestational age and maternal HCS. After correction for gestational age, there was a low but significant correlation between infant weight and maternal HCS (average r = 0.129) and between HCS and placental weight (average r = 0.308). The mean HCS levels of patients admitted in the late stages of labor was significantly lower than those admitted in the earlier stages. Surprisingly, a significant negative correlation (r = −0.203) was observed between cord GH level and infant weight. The low order of correlation between HCS and infant weight indicates that single HCS determinations drawn during labor are a poor indicator of fetal size.