LAUSR

We greatly appreciate the comments of Dr. Devore on our recent analysis. Our point-by-point responses to the comments are listed below this letter. Response to comment <1>: Thank you for your thoughtful suggestion. There are two reasons of our method to measure umbilical vein (UV) diameter. First, in many previous studies, the diameters were determined using a longitudinal section of the umbilical vein in real-time mode following the “maximum principle.” When the vessel walls presented on screen appear as straight lines with maximum longitudinal length, the maximum diameter can be measured. Second, there are many ultrasound departments in some countries that do not have 3D probes. The “maximum principle” can be wider applied by 2D probes in more regions to measure the diameter of UV. Response to comment <2>: It is known that the measured values of UV are affected by the appearance of fetal movement and fetal breathing movement. Thus, our measurements were performed after waiting for these movements to disappear. Because we turned down “Scale” of pulsed-wave Doppler (20–30 cm/s) to optimize and enlarge the UV spectrum, so Figure 1, F and H of our study looks like “pulsatile” waveform of UV. In many studies, normal UV spectrum also showed slightly “pulsatile” waveform when the “Scale” is in suitable range. The umbilical vein pulsation profile was defined as “waveforms with a maximum flow rate variation of 15% or more.” This is a pathological change. Figure 1, F and H of our study showed the normal UV spectrum with the rate variation lower than 15%. Response to comment <3>: Thank you for pointing out the errors. We have checked all the original equations of our paper and found these equations are correct (Table 1). However, why the standard deviation was greater than the mean value by a factor of 10? So, we checked the final submitted version to the journal, and found the reason. There were some differences between final submission version and online-ahead-ofprint version. The correct information is as follows: in table 1 “Y = 0.313 + 0.016BPDGA-0.000046BPD” should be “Y = 0.313 + 0.016BPD-0.000046 BPD,” “Y = 0.193 + 0.012BPDGA-0.000023BPD” should be “Y = 0.193 + 0.012BPD-0.000023BPD.” “Y = 0.102 + 0.014FLGA-0.000046FL” should be “Y = 0.102 + 0.014FL-0.000046FL,” in table 2 “Y = 0.156GA-0.009GA + 0.000161GA” should be “Y = 0.156–0.009GA + 0.000161GA,” “Y = 0.017 + 0.002BPDGA-0.000009BPD” should be “Y = 0.017 + 0.002BPD-0.000009BPD,” “Y = 0.069GA-0.001BPD + 0.000007BPD” should be “Y = 0.069–0.001BPD + 0.000007BPD,” “Y = 0.003 + 0.001FLGA-0.000011FL” should be “Y = 0.003 + 0.001FL-0.000011FL,” “Y = 0.054 GA-0.001FL + 0.000007FL” should be “Y = 0.054–