P05.28: Evaluation of the fetal heart anatomy at 12 to 16 + 6 weeks of gestation

To establish the normal limits of FHR and reliability of fetal heart anatomy evaluation during obstetric scan at 12 to 16 + 6 weeks of gestation. Analysis of transabdominal ultrasound scans performed in 343 pregnant women at 12 to 16 + 6 weeks of gestation. 2D, M-mode and Doppler techniques were used. Gestational week was established on the basis of CRL, BPD, HC, AC and FL measurements. Demographic factors, obstetrical history and follow up of pregnancies were collected. All data were statistically reviewed (Chi test, Student T test, Mc Person correlation). Maternal age varied between 18 and 44 years (mean 32.7 ± 6) and paternal age: 22–62 years (mean 35.4 ± 7). There were 56% primigravidas, 18% women had a history of two or more deliveries and 14% had one or more abortions. FHR varied between 127 and 185 bpm (mean 151 ± 9). The statistically significant difference was found between FHR at 12 weeks (mean 160 ± 8) and following gestational weeks (149–155 bpm). The r—correlation ratio between FHR and gestational week was −0.41 (ns), maternal age—r = 0.40 (ns), paternal age r = 0.28 (ns) and nuchal translucency r = −0.11 (ns). The ultrasound visualization of four chamber view was possible from 12 weeks (72%) to 14 weeks—full evaluation of fetal heart structures could be done in about half of patients then (54%). The ratio between fetal heart area and fetal chest area varied from 0.22 to 0.29. There was no significant correlation between that ratio and gestational week. Fetal heart rate at 12 to 16 weeks was irrespective of the duration of gestation. Parents' age and nuchal translucency did not have influence on the fetal heart rate. It is possible to evaluate fetal heart anatomy as early as at 12 to 16 weeks. The fetal heart size is then smaller than later in pregnancy.