The safety of fetal pulse oximetry in parturients requiring fetal scalp blood sampling

Objective: To determine whether maternal or fetal morbidity is increased in association with fetal pulse oximetry monitoring using an atraumatic intrapartum transcervical fetal oxisensor. Methods: In a prospective cohort study from January 1993 to June 1996, 196 fetuses were monitored during the intrapartum period with a fetal oximetry sensor placed between the uterine wall and the presenting fetal part. The oxisensors were in position for a median duration of 134 minutes. A total of 101 monitored fetuses underwent intrapartum fetal scalp blood sampling because of nonreassuring heart rate tracings. For a control group, we selected all cases during the same period in which fetal blood sampling was performed in the intrapartum period (n = 949) without pulse oximetry monitoring. Data for maternal and fetal morbidity were evaluated and tested for significant differences by the Mann-Whitney LT test. Results: There was no significant difference in gestational age, birth weight, duration of labor, fetal outcome parameters, cesarean rate, operative vaginal deliveries, episiotomy rate, or perineal injuries between the study and control groups. Similarly, the percentages of neonatal intensive care unit admissions, neonatal resuscitations, and neonatal infections were not statistically different in the two groups. A rare complication in the group with pulse oximetry monitoring was a transient impression of the oxisensor probe on the fetal cheek. The rates of postpartum maternal infections, anemia, or secondary wound disruptions were identical in both groups. Conclusion: There was no increased fetal or maternal morbidity associated with the use of an atraumatic intrapartum fetal pulse oxisensor. (C) 1997 by The American College of Obstetricians and Gynecologists.