REVIEW QUESTION

Which method of monitoring fetal heart rate-cardiotocography or intermittent auscultation-leads to better outcomes for mothers and newborns?

TYPE OF REVIEW

A systematic review of four trials involving more than 13,000 women.

RELEVANCE FOR NURSING

Monitoring the fetal heart rate (FHR) to assess fetal well-being during labor is commonly done by intermittent auscultation or by electronic fetal monitoring, or cardiotocography (CTG). An admission CTG is a common screening test consisting of a short, usually 20-minute, recording of the FHR and uterine activity performed on admission once labor is suspected to have begun. It is not recommended for use in laboring women with low-risk pregnancies, because it is poor at predicting fetal harm during labor and is associated with an increased risk of operative births and other obstetric interventions. Despite this, the admission CTG continues to be widely used in developed countries. Questions remain, however, about its effect on neonatal morbidity and mortality, and on maternal morbidity in women with non-low-risk pregnancies.

CHARACTERISTICS OF THE EVIDENCE

This review is an update of a review published in 2012. Randomized and quasi-randomized trials comparing admission CTG with intermittent auscultation of the FHR in women between 37 and 42 weeks of pregnancy and considered to be at low risk for intrapartum fetal hypoxia and of developing complications during labor were included. The primary outcome measures were maternal incidence of cesarean section, incidence of operative vaginal birth, infant perinatal mortality rate, and severe neurodevelopmental disability assessed at 12 months of age or more.

Four trials were included that together involved more than 13,000 women. The data showed that women allocated to admission CTG had, on average, a higher probability of having a cesarean section than women allocated to intermittent auscultation, although this difference was not statistically significant. No differences in the average treatment effect between women allocated to admission CTG and those allocated to intermittent auscultation in instrumental vaginal birth or perinatal mortality rate were reported. No data reported severe neurodevelopmental disability at or beyond 12 months of age.

BEST PRACTICE RECOMMENDATIONS

Based on the latest and best available evidence, admission CTG confers no benefits to either the woman or the fetus. Moreover, a CTG conducted on admission may increase cesarean section rates by approximately 20%. However, caution should be taken in translating these findings to practice as the trials were not powered adequately, their quality ranged from moderate to very low, and all were conducted in developed countries. Relevance to developing countries will depend on FHR monitoring practices in each location.

RESEARCH RECOMMENDATIONS

Research to discover the reasons maternity care professionals persist in performing admission CTGs, as well as implementation studies to change this practice, is needed. The trials in this review reflect only the outcomes of women undergoing spontaneous or induced labor, and in the largest trial women whose amniotic fluid was clear. Additional studies that evaluate women admitted with signs of labor and where the color of the amniotic fluid is not known would expand our knowledge of the benefits of admission CTG.

REFERENCE