Relationship between maximal respiratory pressures and multiple childbearing in Brazilian middle-aged and older women: A cross-sectional community-based study

OBJECTIVE: Previous studies show that multiparity and a number of chronic conditions are correlated among women. Also, low respiratory muscle strength has been associated to adverse health outcomes such as chronic lung disease and early mortality. This study aimed to investigate associations between the number of lifetime pregnancies and maximal inspiratory/expiratory pressures. METHODS: In a cross-sectional study, 204 women ages 41–80 years-old, from the rural community of Santa Cruz, Brazil, provided data regarding demographics, socioeconomic characteristics, health behaviors, and number of lifetime pregnancies (≤3, 4–6 or ≥7). Maximal respiratory pressures were measured with a digital manometer. Multiple linear regression analysis was used to examine the association of multiple childbearing on maximal respiratory pressures. RESULTS: Of the participants, 44.1% had ≤3 pregnancies, 30.4% had 4–6 pregnancies and 25.5% had >7 pregnancies. In the unadjusted analyses, maximal inspiratory and expiratory pressures varied significantly according to multiple childbearing categories. After adjustment, the values remained statistically significant only for maximal expiratory pressure. Compared to women with ≤3 lifetime pregnancies, those who had ≥7 pregnancies had significantly lower maximal expiratory pressure values (β = -18.07, p = 0.01) CONCLUSION: Multiple childbearing appears to be negatively associated with maximal respiratory pressures; women with a higher number of lifetime pregnancies had lower values of maximal respiratory pressures when compared to those with fewer pregnancies. This association may be due to biomechanical changes in the respiratory muscles promoted by multiple lifetime pregnancies. This finding indicates a need to motivate women, from the prenatal to postpartum period, to safely exercise their respiratory muscles, including abdominal muscle exercises as well as respiratory muscle training.