Normal ranges of fetal heart rate values for healthy fetuses in Poland, as determined by ultrasound between weeks 18 and 29 of gestation

Abstract

Background: Fetal heart rate (FHR) is commonly used to assess fetal well-being. Aims:The aim was to establish normal ranges of FHR during pregnancy by umbilical artery (UMB-A) Doppler analysis in a healthy Polish population. Methods:The study was conducted in a tertiary center for fetal cardiology. Data on gestational age (GA), FHR measured on UMB-A, cardiac problems, and extracardiac problems were collected. All fetuses underwent echocardiographic examination. The inclusion criteria comprised normal fetal biometry and biophysical profile, labels of "normal heart anatomy and normal heart function", "no extracardiac malformations", and no "extracardiac anomalies".Results: Based on the data from 258 healthy fetuses, a scatter graph with regression line giving a prognosis of normal values for FHR during pregnancy was prepared (95% confidence interval). The regression equation for FHR, as function of GA in weeks, was found to be: FHR (beats/minute) = 149 -GA according to biometry (weeks) × 0.22; (r = -0.1032; P = 0.098); FHR (beats/ /minute) = 148 -GA according to the last menstrual period (weeks) × 0.16; (r = -0.0722; P = 0.253). The 5 th , 50 th , 95 th percentiles, mean and standard deviation of FHR between weeks 18 and 29 of gestation were calculated. Conclusions:We present the normal ranges for FHR measured on UMB-A for weeks 18 to 29 of gestation in healthy fetuses with normal heart function and anatomy. The obtained values may be of value to departments of obstetrics and should be considered important elements of the basic fetal ultrasound report.