FDA Approves New Fetal Monitoring System
Conventional monitors used today measure fetal heart rate and uterine contractions. Physicians use these measurements, along with other factors, to decide if labor can continue normally or if a Cesarean delivery is indicated.
The new monitor, the OxiFirst Fetal Oxygen Saturation Monitoring System, manufactured by Mallinckrodt/Nellcor Perinatal Business (Pleasanton, CA), represents the first major technological development in fetal monitoring since electronic monitoring was first introduced in the 1960s. The system builds on pulse oximetry technology initially developed in the 70s and 80s by Nellcor for adult and pediatric use.
The OxiFirst system is only to be used along with conventional electronic fetal monitoring when the fetal heart rate is "non-reassuring," i.e. when it indicates that the baby may be in distress due to lack of adequate oxygen.
The OxiFirst monitor consists of a fetal sensor that emits and detects red and infrared light, a connecting cable, and a microprocessor-controlled monitoring console. The monitor displays fetal oxygen saturation as the percentage of oxygen in the fetus's blood. During use, the OxiFirst sensor is inserted into the mother's uterus and placed against the fetus's temple or cheek.
In clinical trials, 508 women were monitored with the OxiFirst monitor and 502 women received standard labor management without the OxiFirst monitor. Women monitored with the OxiFirst system were allowed to continue labor when the fetus had a non-reassuring heart rate and if the OxiFirst monitor showed that the fetal oxygen saturation was above 30%. The study assessed whether use of this new monitor would reduce the Cesarean-section rate due to non-reassuring fetal heart rate.
The study found that the Cesarean rate for non-reassuring heart rate was 10% in the group of women monitored conventionally, compared to 5% in the OxiFirst group. However, the study also found that the overall Cesarean rate between the two groups was unchanged. For reasons not explained by the study, Cesareans for dystocia (difficult labor) increased in the OxiFirst group.
The study showed that the use of the OxiFirst monitor was safe for both the mother and fetus. The rate of adverse events was comparable between the two groups.
To further assess the effect of use of this new monitor on Cesarean rates, Mallinckrodt will conduct a large study in general medical practice.
Source: U.S. Food and Drug Administration