Respiratory muscle strength in pregnancy

Area of Science:

• Physiology
• Obstetrics
• Respiratory Medicine

Background:

• Studies on respiratory muscle strength during pregnancy are limited.
• Understanding these pressures is crucial for maternal and fetal well-being.

Purpose of the Study:

• To document mean maximum inspiratory (PImax) and expiratory (PEmax) pressures in first-time pregnant women.
• To explore the relationship between anthropometric, morphologic, and physiologic variables and these respiratory pressures.

Main Methods:

• 120 primigravid women (20-29 years old, euthrophic, low-risk) were studied from week 5 to 40 of gestation.
• Maximum inspiratory (PImax) and expiratory (PEmax) pressures were measured.
• Associations with gestational age, anthropometric measures (height, fundal height), and inter-recti abdominis distance were analyzed.

Main Results:

• Mean PImax was 88.5 ± 16.52 cmH2O and mean PEmax was 99.76 ± 18.19 cmH2O.
• No significant association was found between gestational age and PImax or PEmax.
• Height was the only anthropometric variable significantly associated with PImax (r=0.20, p=0.02).
• PImax showed an independent association with height and dyspnea during exertion (PImax = 0.6 + 57.9*height - 1.68*dyspnea).

Conclusions:

• Maximum inspiratory and expiratory pressures do not appear to be significantly altered during pregnancy.
• Height is a predictor of inspiratory muscle strength.
• Further longitudinal studies are recommended to track changes over time.