The four-dimensional ultrasonography effects on changes of foetal and maternal heart rate: Are these interventions safe?

Background and Objectives: Ultrasonography is one of the prenatal diagnostic methods, which is applied to detect any genetic diseases, defects, and anomalies. This study aimed to evaluate the changes in foetal heart rate (FHR) and maternal heart rate due to four-dimensional (4D) ultrasonography immediately after ultrasound imaging. Materials and Methods: This descriptive study was conducted on the foetus of pregnant women who were referred to the ultrasound clinic for undergoing a (4D) ultrasonography. After filling out the demographic forms, the baseline FHR was measured at the beginning of the 2D and 4D ultrasonography. All haemodynamic parameters were recorded at the end of the combined ultrasound imaging. Data were compared before and after ultrasonography using paired t-test and correlation coefficient in SPSS software. Analysis of covariance (ANCOVA) was used to adjust the effect of baseline heart rate in foetus and sonography. Results: The mean duration of combined 2D and 4D ultrasound imaging was 1249.8 ± 257 s. Moreover, the mean 4D ultrasound duration was 246.1 ± 83.3. A significant decrease were observed in maternal heart rate following the combined ultrasonography (P