Lower second-trimester fetal heart rate was associated with longer neonatal QTc intervals (367 vs. 362 ms between outer quartiles; p<0.05), while first-trimester FHR showed no association.
Cohort (n=7,998)
Is fetal heart rate associated with the neonatal QTc interval in a general population?
Second-trimester, but not first-trimester, fetal heart rate is inversely associated with the neonatal QTc interval, highlighting a gestation age-dependent relationship.
Effect estimate: adjusted difference -0.16410 -3 (95% CI -0.88010 - to -0.11010 -4)
p-value: p=<0.05
Background: Fetal bradycardia has been reported in neonates with congenital long QT syndrome, but it remains unknown whether there is a general association between fetal heart rate (FHR) and the neonatal QT interval.Objective: We examined whether first-and second-trimester FHR measurements were associated with the neonatal QT interval. Methods:We investigated neonates from a large population-based cohort study with available electrocardiograms (ECG) and first trimester FHR measurements (FHR1).We also investigated a subgroup with second-trimester FHR data (FHR2).The neonatal QTc interval was the primary outcome variable.Univariate and multiple regression analyses were also performed. Results:The study cohort included 7,998 neonates (48.4% girls) with a median age of 11 days (interquartile range, IQR 7-14) at ECG recording.At a median gestation age (GA) of 90 days, we found a median FHR1 of 159 beats per minute (bpm; IQR 155-164) and no association with the QTc interval (adjusted difference 0.40710; 95%CI:-0.65610to 0.14710; p>0.05).The median FHR2 (available in 2,202 neonates; median GA 140 days) was 148 bpm (IQR 144-153), and lower FHR2 values were associated with longer QTc intervals (QTcFridericia 367 vs. 362 ms between outer quartiles).This association remained significant after multifactorial adjustment (adjusted difference -0.16410 -3 ; 95%CI:-0.88010 - to -0.11010 -4 ; p<0.05). Conclusions:Second-trimester FHR is associated with longer neonatal QTc interval, while no association was observed between first trimester FHR and the QTc interval.These findings suggest a GA-dependent association emphasizing the importance of considering GA when evaluating FHR and neonatal QT intervals.
Lam et al. (Sun,) conducted a cohort in Neonates (n=7,998). Fetal heart rate (FHR) measurements was evaluated on Neonatal QTc interval (adjusted difference -0.16410 -3, 95% CI -0.88010 - to -0.11010 -4, p=<0.05). Lower second-trimester fetal heart rate was associated with longer neonatal QTc intervals (367 vs. 362 ms between outer quartiles; p<0.05), while first-trimester FHR showed no association.