Fig. 2

IVPD, and EL_AVG in different phases (D1-D2-D3) of left ventricular diastole in the healthy second-trimester foetus
D1: isovolumic relaxation period; D2: early diastole; D3: late diastole; each column is D1, D2, and D3 from top to bottom; A-C: the absolute values of IVPD and IVPG in different phases of left ventricular diastole (D1-D2-D3) show a decreasing-increasing trend; D -F: different phases of left ventricular diastole Phase (D1-D2-D3) EL_AVG showed an increasing trend