Impact of COVID-19 pandemic restrictions on pregnancy duration and outcome in Melbourne, Australia.

OBJECTIVE: To investigate the effect of restriction measures implemented to mitigate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission during the coronavirus disease 2019 (COVID-19) pandemic on pregnancy duration and outcome. METHODS: A before-and-after study was conducted with cohort sampling in three maternity hospitals in Melbourne, Australia, including women who were pregnant when restriction measures were in place during the COVID-19 pandemic (estimated conception date between 1 November 2019 and 29 February 2020) and women who were pregnant before the restrictions (estimated conception date between 1 November 2018 and 28 February 2019). The primary outcome was delivery before 34 weeks' gestation or stillbirth. The main secondary outcome was a composite of adverse perinatal outcomes. Pregnancy outcomes were compared between women exposed to restriction measures and unexposed controls using the χ-square test and modified Poisson regression models, and duration of pregnancy was compared between the groups using survival analysis. RESULTS: In total, 3150 women who were exposed to restriction measures during pregnancy and 3175 unexposed controls were included. Preterm birth before 34 weeks or stillbirth occurred in 95 (3.0%) exposed pregnancies and in 130 (4.1%) controls (risk ratio (RR), 0.74 (95% CI, 0.57-0.96); P = 0.021). Preterm birth before 34 weeks occurred in 2.4% of women in the exposed group and in 3.4% of women in the control group (RR, 0.71 (95% CI, 0.53-0.95); P = 0.022), without evidence of an increase in the rate of stillbirth in the exposed group (0.7% vs 0.9%; RR, 0.83 (95% CI, 0.48-1.44); P = 0.515). Competing-risks regression analysis showed that the effect of the restriction measures on spontaneous preterm birth was stronger and started earlier (subdistribution hazard ratio (HR), 0.81 (95% CI, 0.64-1.03); P = 0.087) than the effect on medically indicated preterm birth (subdistribution HR, 0.89 (95% CI, 0.70-1.12); P = 0.305). The effect was stronger in women with a previous preterm birth (RR, 0.42 (95% CI, 0.21-0.82); P = 0.008) than in parous women without a previous preterm birth (RR, 0.93 (95% CI, 0.63-1.38); P = 0.714) (P for interaction = 0.044). Composite adverse perinatal outcome was less frequent in the exposed group than in controls (all women: 2.1% vs 2.9%; RR, 0.73 (95% CI, 0.54-0.99); P = 0.042); women with a previous preterm birth: 4.5% vs 8.4%; RR, 0.54 (95% CI, 0.25-1.18); P = 0.116). CONCLUSIONS: Restriction measures implemented to mitigate SARS-CoV-2 transmission during the COVID-19 pandemic were associated with a reduced rate of preterm birth before 34 weeks. This reduction was mainly due to a lower rate of spontaneous prematurity. The effect was more substantial in women with a previous preterm birth and was not associated with an increased stillbirth rate. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

This Is What COVID-19 Survival Looks Like: 129Xe MRI, Oscillometry and Pulmonary Function Measurements

PURPOSE: COVID-19 lung infection has severe consequences that may persist following recovery including impaired oxygen transfer and local and systemic inflammation.1 Although the long-term consequences of COVID-19 are poorly understood, preliminary CT evidence suggests permanent structural damage2 may reduce lung function in some survivors. Oscillometry and multiple breath washout (MBW) may be well suited to detecting small airway abnormalities due to increased sensitivity to heterogeneous small airway and alveolar tissue abnormalities compared to spirometry.3,4 Likewise, inhaled 129Xe MRI provides a unique, quantitative measures of airway and alveolar structure/function through ventilation defect percent (VDP) and the apparent diffusion coefficient (ADC).5 We hypothesized that 129Xe MRI, oscillometry and MBW would reveal abnormal findings in the absence of abnormal pulmonary function test results in COVID-19 survivors. METHODS: Participants with a positive COVID-19 test that were being followed for long-term sequelae provided written informed consent up to three months post-recovery to 129Xe MRI, MBW, oscillometry and spirometry. Ventilation defect percent (VDP) and ADC were calculated using semi-automated segmentation tools.6 Significant differences were determined using paired-sample t-tests. RESULTS: Participants without prior history of chronic respiratory disease (n=8), those with a prior diagnosis of COPD (n=2) and asthma (n=4) were recruited. Mean FEV1 was normal with no post-bronchodilator (post-BD) response (pre-BD=88±19%pred, post-BD=88±20%pred, p=.87), however MBW lung clearance index (LCI) significantly increased (pre-BD=130±46%pred, post-BD=153±47%pred, p=.02). 129Xe MRI VDP was abnormal (pre-BD=7±7%, post-BD=6±5%, p=.46) while ADC (0.052±0.003cm2/s) was similar to values previously evaluated in participants with COPD.7,8 Airway resistance (pre-BD=0.85±0.69, post-BD=0.56±0.72 cmH2O·s/L, p=.010) and reactance (pre-BD=14±13 cmH2O/L, post-BD=9±9 cmH2O/L, p=.036) significantly improved post-BD, were elevated, and similar to previously reported asthma and COPD values.9 No significant post-BD differences were observed between participants with and without obstructive diseases. CONCLUSIONS: Abnormal ADC and VDP in symptomatic participants after COVID-19 recovery were consistent with small airway and alveolar damage. Abnormal oscillometry measurements improved post-bronchodilator, suggesting small airway damage and decreased tissue elastance. An unexpected increase in LCI post-bronchodilator warrants further investigation and may be due to preferential bronchodilator response in certain airways. 129Xe MRI, oscillometry and MBW measurements detect lung function impairment in survivors and may provide useful measures for longitudinal monitoring and treatment response.