Maternal and fetal oxytocin levels at parturition in a paraplegic woman

Maternal and fetal oxytocin levels were measured by radioimmunoassay in a paraplegic woman with a spinal cord lesion at $\text{T-4}\text{T-5}$ who went into spontaneous labor at 39 wk of pregnancy and delivered vaginally a male infant weighing 3220 g. She showed signs of autonomic hyperreflexia during labor. Maternal plasma oxytocin was 3–12 pg/ml in 3 blood samples and undetectable in another 4 taken during the first stage, with a surge of 38 pg/ml at delivery of the fetus. Oxytocin levels were 73 pg/ml in umbilical venous plasma, and 14 pg/ml in amniotic fluid. The findings indicate that the fetus was an important source of oxytocin to the maternal uterus.