Fig. 1

Evaluation of the foetal main pulmonary artery (MPA) and measurement of Doppler indices. A sonographic short-axis view of normal foetal heart at 35 weeks and 3 days of gestational age. Right (R) and left (L) pulmonary arteries are shown branching from the Main pulmonary artery (MPA). Anteriorly and to the right of MPA are aorta and SVC. B Colour Doppler image in short-axis view of normal foetal heart at 35 weeks and 3 days of gestational age. C Foetal Main pulmonary artery velocity waveforms with measurement of Doppler indices in a foetus at 35 weeks and 6 days of gestational age. On post-natal follow-up, the neonate did not develop RDS. D Foetal Main pulmonary artery velocity waveforms with measurement of Doppler indices in a foetus at 35 weeks and 3 days of gestational age which subsequently developed RDS