To determine the effect of ethnicity on fetal heart rate (FHR) variation.Methods
A prospective study was conducted of 27 consecutive black women (of African or Caribbean ethnic origin) and 79 consecutive white women (of European ethnic origin) volunteers attending the antenatal clinic, with uncomplicated singleton pregnancies of at least 34 completed weeks' gestation. The participants had cardiotocography performed with an FHR monitor connected to a Sonicaid System 8002 computer. We studied the mean FHR, long-term FHR variation, short-term FHR variation, the number of accelerations, and the reactivity of the FHR.Results
The long-term FHR variation in centiles corrected for gestational age, the duration in minutes of episodes of high FHR variation, the long-term FHR variation in beats per minute during episode of high FHR variation, and the number of accelerations were significantly reduced in fetuses of black women compared with those in fetuses of white women (P = .007, P = .005, P = .009, and P = .006, respectively, Mann-Whitney U test). The fetuses of black women had a significantly higher proportion of nonreactive traces (P = .009, Fisher exact test). However, there was no significant difference in the short-term FHR variation be-tween the two groups (P = .101).Conclusion
There is an ethnic difference in FHR variation, with significantly reduced long-term variation in black fetuses.