Related Experiment Video
Updated: Aug 18, 2026
Continuous Telemetric In Utero Tracheal Pressure Measurements in Fetal Lambs
Published on: December 22, 2023
Analysis of fetal breathing movements at 30-38 weeks of gestation
Jesús Florido1, Elena Cortés, Marcos Gutiérrez
1Department of Obstetrics and Gynecology, Escuela Universitaria de Ciencias de la Salud and Facultad de Medicina, University of Granada, Granada, Spain. jflorido@ugr.es
Aims:
This study reports the changes in patterns of fetal breathing movements recorded with a photogrammetric method in three successive periods of gestation.
Methods:
Respiratory movements were studied in fetuses of 28 healthy women with uncomplicated pregnancies of 30-38 weeks of gestation. Women were divided into three groups according to gestational age of the fetus: 30-32 weeks, 7 fetuses; 33-36 weeks, 9 fetuses; and 37-38 weeks, 12 fetuses. Sonographic images of the fetuses were recorded on videotape, digitized (1 image per 0.12 s) and analyzed with specially developed software.
Results:
The proportion of fetuses in each age group for which movements were detectable was similar in all three groups, as was the frequency of movements. Duration of a complete respiratory cycle, the inspiratory phase and the expiratory phase tended to be shorter at 33-36 weeks of gestation than in younger and older fetuses. Fetuses in the 30-32-week group had slower breathing rates than fetuses in the two older groups.
Conclusions:
The photogrammetric technique revealed differences in some patterns of fetal breathing movements between weeks 30-32, 33-36 and 37-38 of gestation. The data provide a sound basis for relating changes in fetal breathing movements with physiological and anatomical changes that occur as the respiratory system matures.
Related Concept Videos
01:29Assessment of Ventilation II: Respiratory Depth and Rhythm
Respiratory depth measures the volume of air inhaled or exhaled during a breath. It can vary from shallow to deep and typically remains consistent when a person is at rest or asleep. Occasionally, individuals will automatically inhale deeply, known as sighing, which inflates the lungs with more air than normal breathing.
To assess respiratory depth, observe the degree of chest excursion or movement:
01:26Respiratory Volumes and Capacities I
01:31Respiratory System Abnormal Finding II: Palpation and Auscultation
Palpation Findings
During a respiratory assessment, palpation can reveal several vital abnormalities:
01:20Assessment of Ventilation I: Respiratory Rate
A Ventilation assessment is critical for monitoring a patient's health status. Respiration, one of the most accessible vital signs, provides insights into the function of numerous body systems and can indicate serious health issues, such as brainstem injuries from head trauma.
Critical Guidelines for Assessing Ventilation: