Objectives To explore the impact of COVID-19 lockdown on premature birth rates in Denmark Design Nationwide register-based prevalence proportion study. Participants 31,180 live singleton infants born in Denmark between March 12, and April 14, from 2015 to 2020 Main outcome measures The Main outcome measure was the odds ratio of premature birth, per preterm category, during the lockdown period compared with the calendar match period in the five previous years. Results A total of 31 180 newborns were included in the study period, of these 58 were born extremely premature (gestational age below 28 weeks). The distribution of gestational ages was significantly different (p = 0.004) during the lockdown period compared to the previous five years. The extremely premature birth rate during the lockdown was significantly lower than the corresponding mean rate for the same dates in the previous years (odds ratio 0.09 [95 % CI 0.01 - 0.04], p < 0.001). No significant difference between the lockdown and previous years was found for other gestational age categories. Conclusions The birth rate of extremely premature infants decreased significantly (~90 % reduction) during the Danish nationwide lockdown from a stable rate in the preceding five years. The reasons for this decrease are unclear. Identification of possible causal mechanisms might stimulate changes in clinical practice. Ideally, some cases of extreme prematurity are preventable which may decrease infant morbidity and mortality.

中文翻译：

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丹麦全国COVID-19封锁期间早产率的变化：一项基于全国登记册的患病率研究

目的在丹麦设计全国基于登记的患病率研究中，探讨COVID-19锁定对早产的影响。参与者2015年至2020年3月12日至4月14日期间在丹麦出生的31,180例单胎活婴儿主要结局指标主要结局指标是锁定期间每个早产类别的早产几率（与日历匹配期相比）。前五年。结果研究期间共纳入31 180例新生儿，其中58例出生过早（胎龄低于28周）。与前五年相比，锁定期间的胎龄分布有显着差异（p = 0.004）。封锁期间的极早出生率大大低于往年相同日期的相应平均率（赔率为0.09 [95％CI 0.01-0.04]，p <0.001）。对于其他胎龄类别，锁定与前几年之间没有显着差异。结论在丹麦全国范围内的禁闭行动中，极早产儿的出生率从前五年的稳定水平显着下降（降低了约90％）。这种减少的原因尚不清楚。确定可能的原因机制可能会刺激临床实践的变化。理想情况下，某些极端早产是可以预防的，这可能会降低婴儿的发病率和死亡率。对于其他胎龄类别，锁定与前几年之间没有显着差异。结论在丹麦全国范围内的禁闭行动中，极早产儿的出生率从前五年的稳定水平显着下降（降低了约90％）。这种减少的原因尚不清楚。确定可能的原因机制可能会刺激临床实践的变化。理想情况下，某些极端早产是可以预防的，这可能会降低婴儿的发病率和死亡率。对于其他胎龄类别，锁定与前几年之间没有显着差异。结论在丹麦全国范围内的禁闭行动中，极早产儿的出生率从前五年的稳定水平显着下降（降低了约90％）。这种减少的原因尚不清楚。确定可能的原因机制可能会刺激临床实践的变化。理想情况下，某些极端早产是可以预防的，这可能会降低婴儿的发病率和死亡率。这种减少的原因尚不清楚。确定可能的原因机制可能会刺激临床实践的变化。理想情况下，某些极端早产是可以预防的，这可能会降低婴儿的发病率和死亡率。这种减少的原因尚不清楚。确定可能的原因机制可能会刺激临床实践的变化。理想情况下，某些极端早产是可以预防的，这可能会降低婴儿的发病率和死亡率。