Plasma copeptin may not be a sensitive marker of perinatal stress in healthy full-term growth-restricted fetuses.

OBJECTIVE: Intrauterine-growth-restriction-(IUGR) is associated with chronic fetal stress, as well as a phase of enhanced fetal/early postnatal insulin sensitivity, followed by a later emergence of insulin resistance. We aimed to prospectively investigate concentrations of copeptin, a sensitive marker of stress and insulin resistance, in IUGR versus appropriate-for-gestational-age-(AGA) fetuses.

METHODS: Cord blood copeptin concentrations were determined by ELISA in well-defined, non-distressed at birth, asymmetric IUGR (n = 30) and AGA (n = 20) full-term pregnancies. Doppler studies were indicative of placental insufficiency.

RESULTS: Cord blood copeptin concentrations were similar in IUGR cases and AGA controls, after controlling for delivery mode. Copeptin concentrations were markedly elevated in vaginally delivered fetuses (p = 0.001). No association was recorded between fetal copeptin concentrations and maternal age, parity, gestational age, or fetal gender.

CONCLUSIONS: Cord blood copeptin concentrations are probably not affected by IUGR at term, in the absence of fetal distress, possibly due to a balance between copeptin up-regulation by chronic fetal stress, on one hand, and copeptin down-regulation in the presence of increased insulin sensitivity, on the other hand; thus, copeptin may not be a sensitive marker of chronic perinatal stress in healthy asymmetric IUGR infants. Cord blood copeptin seems to primarily reflect perinatal stress associated with delivery mode.