The prognostic accuracy of short term variation of fetal heart rate in early-onset fetal growth restriction: A systematic review.

OBJECTIVE: Cardiotocography (CTG) is an important tool for fetal surveillance in severe early-onset fetal growth restriction (FGR). Assessment of the CTG is usually performed visually (vCTG). However, it is suggested that computerized analysis of the CTG (cCTG) including short term variability (STV) could more accurately detect fetal compromise. The objective of this study was to systematically review the literature on the association between cCTG and perinatal outcome and the comparison of cCTG with vCTG. STUDY DESIGN: A systematic search was performed in MEDLINE, EMBASE and Google Scholar. Studies were included that assessed prognostic accuracy of STV or compared STV to vCTG in patients with FGR. Risk of bias and concerns about applicability were assessed with the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies-2) instrument. RESULTS: Of the 885 records identified in the search, five cohort studies (387 patients) were included. We found no randomized studies comparing STV with visual CTG in patients with FGR. The risk of bias of all studies was generally judged as 'low'. One small study found an association of low STV with neonatal acidosis. One study observed no association of STV with long-term outcome. Composite analysis of all five studies showed a non-significant relative risk for acidosis after a low STV of 1.4 (95% CI 0.6-3.2, N = 387). Further meta-analysis was hampered due to heterogeneity in outcome reporting and use of different thresholds. CONCLUSION: The evidence from the included studies did not support an association of STV and short or long term outcome. However, available data are limited and heterogeneous, and influenced by management based on STV. Solid evidence from a randomized controlled trial comparing STV with vCTG including long term infant outcome is needed before STV can be used clinically for timing of delivery in patients with FGR.

How to monitor pregnancies complicated by fetal growth restriction and delivery before 32 weeks: post-hoc analysis of TRUFFLE study.

OBJECTIVES: In the recent TRUFFLE study, it appeared that, in pregnancies complicated by fetal growth restriction (FGR) between 26 and 32 weeks' gestation, monitoring of the fetal ductus venosus (DV) waveform combined with computed cardiotocography (CTG) to determine timing of delivery increased the chance of infant survival without neurological impairment. However, concerns with the interpretation were raised, as DV monitoring appeared to be associated with a non-significant increase in fetal death, and some infants were delivered after 32 weeks, at which time the study protocol no longer applied. This secondary sensitivity analysis of the TRUFFLE study focuses on women who delivered before 32 completed weeks' gestation and analyzes in detail the cases of fetal death. METHODS: Monitoring data of 317 pregnancies with FGR that delivered before 32 weeks were analyzed, excluding those with absent outcome data or inevitable perinatal death. Women were allocated randomly to one of three groups of indication for delivery according to the following monitoring strategies: (1) reduced fetal heart rate short-term variation (STV) on CTG; (2) early changes in fetal DV waveform; and (3) late changes in fetal DV waveform. Primary outcome was 2-year survival without neurological impairment. The association of the last monitoring data before delivery and infant outcome was assessed by multivariable analysis. RESULTS: Two-year survival without neurological impairment occurred more often in the two DV groups (both 83%) than in the CTG-STV group (77%), however, the difference was not statistically significant (P = 0.21). Among the surviving infants in the DV groups, 93% were free of neurological impairment vs 85% of surviving infants in the CTG-STV group (P = 0.049). All fetal deaths (n = 7) occurred in the groups with DV monitoring. Of the monitoring parameters obtained shortly before fetal death in these seven cases, an abnormal CTG was observed in only one case. Multivariable regression analysis of factors at study entry demonstrated that a later gestational age, higher estimated fetal weight-to-50th percentile ratio and lower umbilical artery pulsatility index (PI)/fetal middle cerebral artery-PI ratio were significantly associated with normal outcome. Allocation to DV monitoring had a smaller effect on outcome, but remained in the model (P < 0.1). Abnormal fetal arterial Doppler before delivery was significantly associated with adverse outcome in the CTG-STV group. In contrast, abnormal DV flow was the only monitoring parameter associated with adverse outcome in the DV groups, while fetal arterial Doppler, STV below the cut-off used in the CTG-STV group and recurrent decelerations in fetal heart rate were not. CONCLUSIONS: In accordance with the findings of the TRUFFLE study on monitoring and intervention management of very preterm FGR, we found that the proportion of infants surviving without neuroimpairment was not significantly different when the decision for delivery was based on changes in DV waveform vs reduced STV on CTG. The uneven distribution of fetal deaths towards the DV groups was probably a chance effect, and neurological outcome was better among surviving children in these groups. Before 32 weeks, delaying delivery until abnormalities in DV-PI or STV and/or recurrent decelerations in fetal heat rate occur, as defined by the study protocol, is likely to be safe and possibly benefits long-term outcome. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.