The causal relationship between the high number of births and the decline in spirometric rates in Tunisian women was the focus of a series of scientific research conducted by Professor Helmy Ben Saad, Professor of Physiology and Functional Explorations at the Faculty of Medicine in Sousse, starting in 2001, the latest of which was a research whose results were published in November. Past in BMC Pulmonary Medicine.
Helmy Ben Saad is an international expert in spirometry, and he leads the ranking of spirometry experts in Africa, and he also heads the Tunisian Authority for Physiology and Functional Explorations. That as the number of pregnancies increased, the respiratory function deteriorated.
Professor Helmy Ben Saad says that the discovery of the relationship between the number of pregnancies and the respiratory function was a coincidence. In 2001, in the context of his work on his medical thesis, and while analyzing the factors affecting the respiratory data of the elderly population of Tunisia, a strong relationship was discovered between the number of pregnancies. and spirometry.
Since then, specific studies have been conducted that have all confirmed the hypothesis linking increased pregnancies with deterioration of respiratory function.
Helmy bin Saad is an international expert in spirometry and leads the ranking of experts in this field in Africa (Al-Jazeera)
The equation between fertility and healthy longevity
Professor Helmy bin Saad believes that there is a significant negative apparent correlation between the number of children born and the healthy age of women, as each additional child reduces 0.74 years of the healthy age. Towards obstruction of the airways and decreased inspiratory muscle strength (reduction of maximal inspiratory pressure), which necessitates adopting the number of pregnancies as an independent variable in computational models that predict normal values of spirometry variables.
Professor Ben Saad indicates that these results apply to Tunisian women and to women in countries characterized by a high rate of births in general.
Multiple births and changes on more than one level
Professor Helmy Ben Saad considers that several hypotheses can be put forward to explain the negative effect of the number of births on women's spirometric parameters.
These hypotheses are based on a set of changes observed by specialists in women's health, including:
Changes in respiratory muscle strength
: Research examining the maximum rates of inspiration and exhalation of healthy females reveals that women with a number of births equal to or greater than 4 have lower rates of inspiratory pressure than women of 60 years of age with a number of births less than 3.
The examination of the maximum rates of inhalation and exhalation is an examination that allows the assessment of the strength of the respiratory muscles that contribute to the breathing mechanism and the cleaning of the airways.
Studying the number of pregnancies in relation to the respiratory system opens new scientific horizons (Al-Jazeera)
Anatomical changes
: According to Bin Saad, pregnancies are related to changes in the mucous membrane of the airway, as an increase in the size of the uterus and the abdominal region leads to a change in the composition of the chest and respiratory muscles.
Chest circumference may increase and respiratory muscles hypertrophy, in addition to a change in the biomechanics of the abdominal muscles.
The effects of these changes can accumulate with repeated pregnancies and lead to a decrease in respiratory muscle tone, and thus a 'deterioration' in spirometric parameters.
Hormonal changes
: Female sex hormones are a putative mediator of lung health, as they control airway smooth muscle, cell proliferation, and inflammation.
Ben Saad points out that it appears that estrogen and progesterone in particular have fluctuating effects on spirometric parameters across the lifespan, as the number of pregnancies is associated with an increase in circulating estrogen.
Because of its recognized inflammatory effects in some female-dominant diseases, circulating estrogens can cause inflammatory lung diseases, including chronic obstructive pulmonary disease.
Hormonal changes can also modify spirometry parameters during the aging process. For example, cortisone secretion in elderly females determines the degree of lung aging. Because elevated levels of cortisone are associated with a decrease in muscle strength, it is possible that cortisone is a mediating factor in the relationship between multiple births. and strength of the respiratory muscles.
The results are representative of Tunisian women and women of countries with a high birth rate (Shutterstock)
Genetic changes:
Professor Helmy Ben Saad says: Some scientists have developed a new hypothesis to explain how higher pregnancies can lead to lower-than-average respiration rates in women linked to the MZ protease inhibitor.
This hypothesis is based on the possibility of increased elastin turnover in MZ protease inhibitors resulting from chronically low protease inhibitor levels.
Autoimmune changes
: Professor Helmy Ben Saad explains that the high number of pregnancies may affect the immune regulation of women, especially smokers.
During pregnancy, the placenta secretes the mineralogyny protein A, pregnancy-associated plasma protein A, which has been shown to increase in the incidence of chronic obstructive pulmonary disease.
Females are also susceptible to several autoimmune disorders, and estrogen appears to regulate the activities of some cells, such as antibody production by B cells and T cell-mediated inflammation.
Since the number of pregnancies is associated with autoimmunity, multiple births may be a predisposition to the development of autoimmunity.
According to some scientists, it is possible that there is an undetermined relationship between the number of pregnancies, autoimmunity, and susceptibility to chronic obstructive pulmonary disease.
An increase in the size of the uterus and the abdominal region leads to a change in the composition of the chest and respiratory muscles (Shutterstock)
Bronchial hyperreactivity
Professor Helmy bin Saad adds to all these hypotheses and the reasons that lead to the deterioration of the respiratory system in women with multiple pregnancies, another factor, which is the hyperactivity of the airways, as he explains that with pregnancy there is a rise in the constricting elements of the airways at the expense of a decrease in the elements that expand the bronchi.
This rise in bronchial hyperreactivity during pregnancy may also be due to a decrease in lung volume and a concomitant decrease in airway lumen.
These effects can accumulate with repeated pregnancies, partly explaining the tendency for hyperinflation and obstructive respiratory defects.
New scientific horizons
Professor Helmy Ben Saad points out that studying the possible effects of the number of pregnancies on spirometric parameters should become a key indicator that must be highlighted and evaluated.
Therefore, this topic may be a promising new direction for pathophysiological research, especially in low-income and lower-middle-income countries.
Thus, future epidemiological and clinical studies of female spirometric parameters will need to include information on the number of pregnancies.