Effect of Parity on FVC and FEV1 during Pregnancy

Abstract

Background and Aim: The influence of pregnancy on pulmonary function is well documented. However, the parity of the woman is usually not taken into consideration in studying pulmonary function in pregnancy. This study aimed to assess lung function pattern in all trimesters of pregnancy as parity increases. Study Design: A longitudinal study. Place and Duration of Study: St Philomena Catholic Hospital, Nigeria between October 2013 and October 2014. Materials and Methods: The study consists of recording chest circumference, Forced Vital Capacity (FVC) and Forced Expiratory Volume in one sec (FEV1) in five groups of female subjects with the Primigravida as control, Nullipara, Primipara, Para 2 and Para 3 pregnant women at various trimesters i.e., 13th week, 24th week and 36th week using a tape rule and computerized Spirometer [19] (Spirolab II Italy) respectively. Each group had 40 subjects making a total of 200 subjects for the study. Results: The study revealed that there was a concomitant increase in FVC and FEV1 as parity increases. FVC and FEV1 were significantly increased (p< 0.001) in Para 3 when compared to the primigravid control subjects. Discussion: The observed improvement in pulmonary function may be due to a progressive increase in the transverse diameter of the chest from a widened subcostal angle. Again, the lumbar lordosis of pregnancy, which is higher in para 3, can explain the increase in chest wall compliance and pulmonary function. Conclusion: Increased parity favorably affects pulmonary function.