Abstract：
BACKGROUND: Results of population-level studies examining the effect of the COVID-19 pandemic on the risks of perinatal death have varied considerably.
OBJECTIVE: To explore trends in the risk of perinatal death among pregnancies beginning prior to and during the pandemic using a pregnancy cohort approach.
METHODS: This secondary analysis included data from singleton pregnancies ≥20 weeks\' gestation in Alberta, Canada, beginning between 5 March 2017 and 4 March 2021. Perinatal death (i.e. stillbirth or neonatal death) was the primary outcome considered. The risk of this outcome was calculated for pregnancies with varying gestational overlap with the pandemic (i.e. none, 0-20 weeks, entire pregnancy). Interrupted time series analysis was used to further determine temporal trends in the outcome by time period of interest.
RESULTS: There were 190,853 pregnancies during the analysis period. Overall, the risk of perinatal death decreased with increasing levels of pandemic exposure; this outcome was experienced in 1.0% (95% confidence interval [CI] 0.9, 1.0), 0.9% (95% CI 0.8, 1.1) and 0.8% (95% CI 0.7, 0.9) of pregnancies with no overlap, partial overlap and complete pandemic overlap respectively. Pregnancies beginning during the pandemic that had high antepartum risk scores less frequently led to perinatal death compared to those beginning prior; 3.3% (95% CI 2.7, 3.9) versus 5.7% (95% CI 5.0, 6.5) respectively. Interrupted time-series analysis revealed a decreasing temporal trend in perinatal death for pregnancies beginning ≤40 weeks prior to the start of the COVID-19 pandemic (i.e. with pandemic exposure), with no trend for pregnancies beginning >40 weeks pre-pandemic (i.e. no pandemic exposure).
CONCLUSIONS: We observed a decrease in perinatal death for pregnancies overlapping with the COVID-19 pandemic in Alberta, particularly among those at high risk of these outcomes. Specific pandemic control measures and government response programmes in our setting may have contributed to this finding.
OBJECTIVE: To explore trends in the risk of perinatal death among pregnancies beginning prior to and during the pandemic using a pregnancy cohort approach.
METHODS: This secondary analysis included data from singleton pregnancies ≥20 weeks\' gestation in Alberta, Canada, beginning between 5 March 2017 and 4 March 2021. Perinatal death (i.e. stillbirth or neonatal death) was the primary outcome considered. The risk of this outcome was calculated for pregnancies with varying gestational overlap with the pandemic (i.e. none, 0-20 weeks, entire pregnancy). Interrupted time series analysis was used to further determine temporal trends in the outcome by time period of interest.
RESULTS: There were 190,853 pregnancies during the analysis period. Overall, the risk of perinatal death decreased with increasing levels of pandemic exposure; this outcome was experienced in 1.0% (95% confidence interval [CI] 0.9, 1.0), 0.9% (95% CI 0.8, 1.1) and 0.8% (95% CI 0.7, 0.9) of pregnancies with no overlap, partial overlap and complete pandemic overlap respectively. Pregnancies beginning during the pandemic that had high antepartum risk scores less frequently led to perinatal death compared to those beginning prior; 3.3% (95% CI 2.7, 3.9) versus 5.7% (95% CI 5.0, 6.5) respectively. Interrupted time-series analysis revealed a decreasing temporal trend in perinatal death for pregnancies beginning ≤40 weeks prior to the start of the COVID-19 pandemic (i.e. with pandemic exposure), with no trend for pregnancies beginning >40 weeks pre-pandemic (i.e. no pandemic exposure).
CONCLUSIONS: We observed a decrease in perinatal death for pregnancies overlapping with the COVID-19 pandemic in Alberta, particularly among those at high risk of these outcomes. Specific pandemic control measures and government response programmes in our setting may have contributed to this finding.
摘要：
背景：研究COVID-19大流行对围产期死亡风险的影响的人群水平研究结果差异很大。
目的：使用妊娠队列方法，探讨在大流行之前和期间开始的妊娠中围产期死亡风险的趋势。
方法：这项次要分析包括艾伯塔省单胎妊娠≥20周的数据，加拿大,从2017年3月5日至2021年3月4日开始。围产期死亡（即死产或新生儿死亡）是考虑的主要结局。此结果的风险是针对妊娠与大流行重叠的妊娠（即没有，0-20周,整个怀孕）。中断的时间序列分析用于进一步确定感兴趣时间段的结果的时间趋势。
结果：在分析期间有190,853例怀孕。总的来说,围产期死亡的风险随着大流行暴露水平的增加而降低;这一结局以1.0%(95%置信区间[CI]0.9,1.0)出现,0.9%（95%CI0.8,1.1）和0.8%（95%CI0.7,0.9）无重叠妊娠，部分重叠和完全重叠的大流行分别。在大流行期间开始的具有较高的产前风险评分的妊娠与之前开始的妊娠相比，其导致围产期死亡的频率较低；分别为3.3％（95％CI2.7，3.9）和5.7％（95％CI5.0，6.5）。中断的时间序列分析显示，在COVID-19大流行开始前≤40周（即大流行暴露）开始的妊娠围产期死亡呈下降趋势，大流行前>40周开始妊娠的趋势(即没有大流行暴露)。
结论：我们观察到与艾伯塔省COVID-19大流行重叠的妊娠围产期死亡减少，特别是在这些结果的高风险人群中。在我们的环境中，具体的大流行控制措施和政府应对计划可能促成了这一发现。
目的：使用妊娠队列方法，探讨在大流行之前和期间开始的妊娠中围产期死亡风险的趋势。
方法：这项次要分析包括艾伯塔省单胎妊娠≥20周的数据，加拿大,从2017年3月5日至2021年3月4日开始。围产期死亡（即死产或新生儿死亡）是考虑的主要结局。此结果的风险是针对妊娠与大流行重叠的妊娠（即没有，0-20周,整个怀孕）。中断的时间序列分析用于进一步确定感兴趣时间段的结果的时间趋势。
结果：在分析期间有190,853例怀孕。总的来说,围产期死亡的风险随着大流行暴露水平的增加而降低;这一结局以1.0%(95%置信区间[CI]0.9,1.0)出现,0.9%（95%CI0.8,1.1）和0.8%（95%CI0.7,0.9）无重叠妊娠，部分重叠和完全重叠的大流行分别。在大流行期间开始的具有较高的产前风险评分的妊娠与之前开始的妊娠相比，其导致围产期死亡的频率较低；分别为3.3％（95％CI2.7，3.9）和5.7％（95％CI5.0，6.5）。中断的时间序列分析显示，在COVID-19大流行开始前≤40周（即大流行暴露）开始的妊娠围产期死亡呈下降趋势，大流行前>40周开始妊娠的趋势(即没有大流行暴露)。
结论：我们观察到与艾伯塔省COVID-19大流行重叠的妊娠围产期死亡减少，特别是在这些结果的高风险人群中。在我们的环境中，具体的大流行控制措施和政府应对计划可能促成了这一发现。
