Spirometric Changes during Pregnancy in Cystic Fibrosis Patients

Clay Wu,Gloria Wu,Lynn Fukushima,Adupa P Rao,Ahmet Baydur

doi:10.4236/ojrd.2021.111002

Abstract

Rationale: Survival and longevity in patients with cystic fibrosis (CF) have improved with new treatments, so that pregnancy can be safely undertaken despite physiologic limitations. Dyspnea still develops in the latter stages of pregnancy. To explain this symptom, we evaluated the effect of pregnancy on lung function before and after delivery. Methods: Records of 23 pregnant patients with CF were retrospectively reviewed for data analysis. Spirometry was recorded prior to pregnancy, at first and third trimesters, and every three months following delivery up to one year. Comparisons between time points were adjusted for age and pre-gestational BMI by analysis of variance (ANOVA). Results: Complete clinical and spirometric data were available for eleven of these patients (13 pregnancies total), obtained between 2009 and 2017. FEV1 and FVC declined significantly from baseline to third trimester (by 8.1%, p Conclusions: The changes in FEV1 and FVC occur as a result of increases in intravascular blood volume and lung water during the third trimester. At the same time, FEV1/FVC increases as there is reversal of bronchiolar constriction with elimination of extracellular fluid and lung water. Furthermore, restoration of end-expiratory lung volume post-partum counteracts reversal of air trapping with resolution of peribronchiolar edema, with FVC remaining unchanged. These changes would explain decrease in dyspnea following delivery in CF patients.

Highlights

With advancements in the treatment and management of cystic fibrosis (CF), patients with CF are increasingly surviving into adulthood
The mean pre-pregnancy FEV1 was 2.49 L ± 0.81 SEM which correlates with 80.9% predicted and mean pre-pregnancy forced vital capacity (FVC) was 3.22 L ± 0.94 SEM which correlates with 83.2% predicted
Five of the eleven patients had normal pre-pregnancy spirometry measurements where FVC and FEV1 were greater than 80% predicted (Table 1)

Summary

Introduction

With advancements in the treatment and management of cystic fibrosis (CF), patients with CF are increasingly surviving into adulthood. A few prior case series have suggested that patients with low FEV1 may be at increased risk for adverse events during pregnancy [2] [3]. Some studies suggest that nutritional status and pancreatic insufficiency could be risk factors for adverse outcome of pregnancy in CF patients. In more recent studies, including a prospective matched cohort comparing pregnant and non-pregnant CF patients, pregnancy was not found to have increased decline in lung function and worsening survival [4] [5] [6]. There is still a limited understanding of the impact of pregnancy on spirometry measurements in women with CF. We retrospectively reviewed the spirometry measurements of pregnant CF patients to evaluate and understand the effect of physiological changes during pregnancy on lung function

Methods

Results

Conclusion