Assessment of the Fetal Heart at 12–14 Weeks of Pregnancy Using B-Mode, Color Doppler, and Spatiotemporal Image Correlation via Abdominal and Vaginal Ultrasonography

This study aimed to evaluate the effect that combining multiple ultrasonographic imaging methods has on the proportion of tests with a satisfactory fetal heart assessment at 12–14 weeks of pregnancy using B-mode, color Doppler, and spatiotemporal image correlation software (STIC) via both the abdominal and vaginal routes. This cross-sectional prospective study involved healthy pregnant women at 12–14 weeks of pregnancy with a crown-rump length (CRL) of 84 mm or shorter. The following four cardiac views were assessed: four-chamber, left and right ventricular outflow tract, and aortic arch views. The same examiner sought to identify these four views using B-mode, color Doppler, and STIC via both the vaginal and abdominal routes. The study determined the proportion of cases and the respective 95 % confidence intervals (CIs) in which all four views were identified. The presence of significant differences in comparisons between methods was analyzed using McNemar’s test. Although 57 pregnant women at 12–14 weeks of pregnancy agreed to participate in the study, 4 were not included because they presented with a CRL longer than 84 mm. Thus, 53 pregnant women were thoroughly assessed and included in the analysis. The combination of B-mode, color Doppler, and STIC via both the abdominal and vaginal routes enabled the highest proportion of identification of the four views (90.6 %; 95 % CI, 79.8–95.9 %). The lowest proportions were observed when B-mode was used alone via both the vaginal route (30.2 %; 95 % CI, 19.5–43.5 %) and the abdominal route (37.7 %; 95 % CI, 25.9–51.2 %). The abdominal route showed results slightly better than those of the vaginal route with all the methods, but the differences were not statistically significant. In the vast majority of the cases, the fetal hearts were properly assessed at 12–14 weeks of pregnancy when several methods were combined using both the abdominal and vaginal routes. However, only one-third of them would have had adequate heart assessment if the B-mode via either the abdominal or the vaginal route had been used alone.