Fetal respiratory movements

Albana Cerekja, MD, PhD*, Juan Piazze MD, PhD**

*   Ultrasound Division, ASL Roma B, Rome, Italy.
** Ultrasound Division, Ceprano Hospital, Ceprano, Italy.


Nasal fluid flow velocity waveforms (NFFVW) is a type of recording of fetal respiratory movement. Fetal breathing movements is commonly assessed by observing the abdomen or thorax. Regular nasal fluid flow velocity waveforms is a sinusoidal wave in which inspiration and expiration phases are regular in amplitude and duration.

Nasal and tracheal flow is represented in two cases, both at 36 weeks.

Inspiration is represented in blue and expiration is represented in red color (considering that the transducer is positioned anteriorly). When Doppler gate is positioned over the color representing the flow, a sinusoidal pulsed wave is obtained.
The same happens with fluid entering and leaving the trachea.
When respiratory movements are present, the umbilical vein flow varies with respiration.

Images 1,2: Image 1 shows a fluid flow during the inspiration. Image 2 shows a fluid flow during the expiration.


Images 3,4: Image 3 shows the irregular nasal fluid flow velocity waveforms. Image 4 shows a regular nasal fluid flow velocity waveforms.


Images 5,6: Image 5 shows a tracheal flow during expiration. Image 6 shows a tracheal flow during inspiration.


Images 7,8: Image 7 shows a pulsed wave of the tracheal flow. Image 8 shows an irregular flow through the umbilical artery and vein which is caused by respiratory movements.


Video 1: Video shows a fluid flow during the inspiration (blue) and expiration (red).


1. Cosmi EV, Anceschi MM, Cosmi E, Piazze JJ, La Torre R. Ultrasonographic patterns of fetal breathing movements in normal pregnancy. Int J Gynaecol Obstet 2003;80(3):285-90.

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