Peak expiratory flow rate: comparison between primiparas in the 3rd trimester of pregnancy and nulliparas

Abstract

Peak expiratory flow rate (PEFR) evaluates the degree of bronchus obstruction and may be an important tool in the control of pregnancy asthma, which affects 4% of pregnant women. This study aims to assess the PEFR of nulliparas and of primiparas in the third trimester of pregnancy, also comparing the values measured to those of an Australian standard table where PEFR is correlated to subjects' height. Furthermore, a possible correlation was searched for, between PEFR, the fundus uterus height, and dyspnea sensation as reported by the pregnant women. The sample was made up of 2 groups, 50 primiparas and 50 nulliparas, aged respectively an average 20.6+3.9 and 20.5+4 years old. No significance was found between PEFR and the fundus uterus height or reported dyspnea. Also, no significant difference (p=0.606) was found between primiparas PEFR (365.0+54.1 l/min) and nulliparas' (359.8+45.9 l/min).
However, both groups' PEFR were lower than the standard (p<0.001). The present study findings suggest that the Australian parameters are not adequate to compare to the studied groups PEFR, pointing to the need to set up Brazilian standards.