Cord and maternal serum meperidine concentrations and clinical status of the infant.

The possible relationship between the use of meperidine during labor and fetal or neonatal distress was investigated by correlating clinical parameters with maternal and cord serum concentrations of meperidine. The serum concentration of meperidine was determined by a radioimmunoassay which is 100-fold more sensitive than previously employed techniques and can detect as little as 0.02 nmol meperidine/ml. The incidence of fetal or neonatal depression following meperidine administration was higher (6 of 17 infants) than in a control group but no correlation between suppression and the route of meperidine administration or the serum meperidine concentrations at the time of delivery was found.