Fetal tachycardia and meconium staining: A sign of fetal infection

A retrospective study was carried out on 72 liveborn babies in whom perinatal infection was suspected. Twenty-nine of the 72 neonates were effectively infected. Analysis of intrapartum FHR recordings showed that tachycardia (base line FHR above 160 beats/min) during labor, occurred more often among infected babies (P < 0.001). When fetal tachycardia is associated with meconium stained amniotic fluid (MSAF), the relative risk of fetal infection is 51 times as great as in babies without MSAF. Fetal tachycardia is not related to maternal fever nor to prematurity. It is not a sign of limited placental or amniotic fluid infection, but implies infection of the fetus itself. Since most infected babies displayed infectious diarrhea immediately at birth, it is suggested that MSAF may eventually be due to antenatal intestinal infection and intrauterine emission of infected stools. Although great caution is advocated for the management of labor in the presence of fetal tachycardia, MSAF should not be always regarded as a sign of acute fetal distress when antenatal infection of the fetus is suspected.