Abstract:
Pregnancy is essentially a physiological process, which involves a great number of physiological changes, affecting virtually all the organ systems in the body. Literature is sparse on the changes in ventilatory function during pregnancy in our locality. The objective of this study is to establish the value of Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1), FEV1/FVC ratio and Peak Expiratory Flow Rate (PEFR) during pregnancy.
The study is a descriptive cross sectional study carried out at the antenatal and booking clinics of the University of Nigeria Teaching Hospital (UNTH), Ituku-Ozalla, Kenechukwu specialist hospital Enugu and Chukwuasokam maternity hospital in Emene. Two hundred (200) normal pregnant women and 100 non-pregnant women were recruited. A standard Spirometer (Micro lab ML3500 MK8, Cardinal Health Germany 234 GMBH) was used to determine the ventilatory function. The mean FVC was 2.93 ± .73 litres in the non-pregnant state but decreased significantly as pregnancy progressed to 2.55± .51 litres in the 3rd trimester. The percentage predicted also decreased significantly from 100.70± 31.11% in the non-pregnant state to 82.30± 19.01 % in the 3ird trimester (P=0.000). The mean FEV1 was 2.55±0.62 litres per second in the non-pregnant state but decreased significantly, as pregnancy progressed to 2.24±0.45 litres/second in the 3rd trimester. Furthermore, the percentage predicted decreased significantly from 102.02± 30.70 31.11% in the non-pregnant state to 82.89±18.32 % in the 3rd trimester (P=0.000). The mean PEFR was 5.38±1.44 litres in the non pregnant state but decreased non significantly as pregnancy progressed to 5.18± 1.42 litres in the 3rd trimester (P=0.883). However, the percentage predicted decreased significantly from 93.4 ± 32.16 % in the non pregnant state to 79.39 ± 20.90 % in the 3rd trimester (P=0.014). The mean FEV1/FVC was 87.56± 2.87 % in the non-pregnant state but increased significantly, as pregnancy progressed to 91.30± 1.91 % in the 3rd trimester. The percentage predicted was 107.37 ± 3.88 % in the non pregnant state, 102.97 ± 1.24 % in the 1st trimester, 109.56 ± 5.33 % in the second trimester and 105.77 ± 5.82% the 3rd trimester ( P=0.000). The FVC and the percentage predicted and the FEV1 and the percentage predicted were within normal range in the non-pregnant and during pregnancy. However, the values decreased significantly, as pregnancy progressed. The decrease in FEV1 during pregnancy is not of same magnitude as the decrease in FVC. Consequently, the FEV1/FVC ratio increased, It can therefore be said that physiological restriction occurs during pregnancy.
