Extremely premature babies can be difficult to monitor using eFHR. fECG (AN24 monitor, Monica Healthcare, Nottingham, UK) is a potential alternative. The goal of this study was to compare tracings in singleton gestations between 24–28 weeks.METHODS:
This was a prospective observational pilot study of hospitalized patients at 24–28 weeks gestation. Twenty-three women were traced for up to 2 hours using eFHR followed by up to 2 hours using fECG. The percentage of time the fetal heart rate was traced during the 2-hour window for each modality was calculated. Differences of >60%, >80%, and >90% total time traced were compared between modalities using McNemar's test. Differences also were assessed for each method between non-obese (BMI<30 kg/m2) and obese (BMI>30 kg/m2) women using Fisher's Exact tests.RESULTS:
Superior performance was found with eFHR at >60% (91.3% versus 43.5%, P<.001) and >80% (73.9% versus 30.4%, P<.01) total time traced, and a trend for superior eFHR performance was found at≥90% (56.5% versus 26.1%, P=.07). All 23 women, however, preferred the greater comfort of the fECG. There were no statistically significant findings between obese and non-obese women for each modality, although there was a trend favoring non-obese women at >80% total time traced using fECG (50.0% versus 9.1%, P=.07).CONCLUSION:
fECG performance in extremely premature gestations was worse than conventional eFHR. fECG may have a role in non-obese patients who are resistant to being traced by eFHR secondary to discomfort. Further studies are necessary to confirm these findings.