Methamphetamine, smoking, and gestational hypertension affect norepinephrine levels in umbilical cord tissues

These studies were undertaken to determine methamphetamine (METH) and smoking effects on umbilical vascular dynamics and pregnancy outcomes.

Umbilical cords (54) were collected prospectively at birth, washed of blood, and stored at -80°C. Cords were thawed and lysates prepared, then catecholamine levels quantified with enzyme-linked immunosorbent assay (ELISA).

Catecholamine levels in umbilical cords were not associated with maternal or gestational age, gravidity, parity, neonatal or placental weight. Neither smoking nor METH affected dopamine or epinephrine. However, smoking (two-fold) and METH (four-fold) decreased norepinephrine and together a 60-fold reduction occurred (p = 0.025). Cesarean section and hypertension were both associated with lower norepinephrine levels (p < 0.001) regardless of drug status. In normotensive pregnancies, smoking and METH significantly decreased norepinephrine levels (two-fold and 3.5-fold each, respectively) with a 40-fold decrease for METH/smoking together.

Depletion of norephinephrine by METH and smoking likely contributes to pregnancy complications, including the higher incidence of respiratory distress and postpartum hemorrhage in cesarean section.