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Fetal Thoracic Circumference and Lung Volume and Their Relation to Fetal Size and Pulmonary Artery Blood Flow
Katarina Hilde1,2, Karin C Lødrup Carlsen2,3, Karen Eline Stensby Bains2,3
1Division of Obstetrics and Gynaecology, Oslo University Hospital, Oslo.
Insights
Fetal thoracic circumference and lung volume show moderate to low correlations with fetal size at 30 weeks gestation. These measurements had weak associations with fetal pulmonary artery blood flow velocity.
Area of Science:
- Prenatal diagnostics
- Fetal development
- Pulmonary medicine
Background:
- Early lung disease origins necessitate understanding fetal thoracic and lung size relationships.
- Fetal size and pulmonary circulation are key factors in lung development.
Purpose of the Study:
- To explore associations between fetal thoracic circumference, lung volume, and overall fetal size.
- To assess the relationship between lung volume, thoracic circumference, and fetal pulmonary artery blood flow velocity.
Main Methods:
- Cross-sectional ultrasound assessment of 447 singleton pregnancies at 30 gestational weeks.
- Measured fetal thoracic circumference, lung volume, abdominal circumference, and femur length.
- Utilized Doppler ultrasound for fetal pulmonary artery blood flow velocity and statistical analyses (Pearson's correlation, multiple linear regression).
Main Results:
- Moderate to low correlations found between thoracic circumference, lung volume, and fetal size parameters (e.g., r=0.64 with abdominal circumference).
- Abdominal circumference showed the strongest correlation with thoracic circumference and lung volume.
- Weak correlations (r≤0.17) observed between thoracic circumference/lung volume and pulmonary artery blood flow velocity measures.
Conclusions:
- Fetal thoracic circumference and lung volume exhibit moderate to low correlations with fetal size at 30 weeks gestation.
- Abdominal circumference is the most closely related fetal biometric parameter.
- Pulmonary artery blood flow velocity shows minimal correlation with thoracic circumference and lung volume.
Objective:
Research on early origins of lung disease suggests the need for studying the relationships of thoracic and lung size with fetal size and pulmonary circulation. The primary aim of this study is therefore to explore the associations between fetal thoracic circumference, lung volume, and fetal size. We also aim to assess if lung volume and thoracic circumference are associated with fetal pulmonary artery blood flow velocity measures.
Methods:
Cross-sectional assessment of singleton pregnancies from the general population (n = 447) at 30 gestational weeks (GW) was performed using ultrasound measurement of fetal thoracic circumference, lung volume, head and abdominal circumference, and femur length. We obtained Doppler blood flow velocity measures from the proximal branches of the fetal pulmonary artery. Associations between variables were studied using Pearson's correlation and multiple linear regression analyses.
Results:
Both thoracic circumference and lung volume correlated with fetal size measures, ranging from r = 0.64 between thoracic circumference and abdominal circumference, to r = 0.28 between lung volume and femur length. Adjustment for gestational age, maternal nicotine use, pre-pregnancy body mass index, and fetal sex marginally influenced the associations with abdominal circumference. The correlations of thoracic circumference and lung volume with pulmonary artery blood flow velocity measures were weak (r ≤ 0.17).
Conclusion:
We found moderate to low correlation between thoracic circumference, lung volume, and fetal size at 30 GW. The closest relationship was with the abdominal circumference. We found low correlations of thoracic circumference and lung volume with pulmonary artery blood flow velocity measures.
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