Association between COVID-19 mandatory lockdown and decreased incidence of preterm births and neonatal mortality

The Temporal Relationship Between the Coronavirus Disease 2019 (COVID-19) Pandemic and Preterm Birth

OBJECTIVE

To evaluate whether preterm birth rates changed in relation to the onset of the coronavirus disease 2019 (COVID-19) pandemic and whether any change depended on socioeconomic status.

METHODS

This is an observational cohort study of pregnant individuals with a singleton gestation who delivered in the years 2019 and 2020 at 1 of 16 U.S. hospitals of the Maternal-Fetal Medicine Units Network. The frequency of preterm birth for those who delivered before the onset of the COVID-19 pandemic (ie, in 2019) was compared with that of those who delivered after its onset (ie, in 2020). Interaction analyses were performed for people of different individual- and community-level socioeconomic characteristics (ie, race and ethnicity, insurance status, Social Vulnerability Index (SVI) of a person's residence).

RESULTS

During 2019 and 2020, 18,526 individuals met inclusion criteria. The chance of preterm birth before the COVID-19 pandemic was similar to that after the onset of the pandemic (11.7% vs 12.5%, adjusted relative risk 0.94, 95% CI 0.86-1.03). In interaction analyses, race and ethnicity, insurance status, and the SVI did not modify the association between the epoch and the chance of preterm birth before 37 weeks of gestation (all interaction P >.05).

CONCLUSION

There was no statistically significant difference in preterm birth rates in relation to the COVID-19 pandemic onset. This lack of association was largely independent of socioeconomic indicators such as race and ethnicity, insurance status, or SVI of the residential community in which an individual lived.

Preterm birth during the COVID-19 pandemic: more, less, or just the same?

OBJECTIVES

Coronavirus disease (COVID-19) and its mitigation measures have been associated with changes in preterm birth (PTB) incidences. The objective of this paper is to summarize and comment on the literature on COVID-19 and PTB and to compare PTB incidence between 2019 (pre-COVID-19) and 2020 (COVID-19) in three Belgian tertiary care hospitals.

METHODS

A non-systematic review on COVID-19 and PTB was performed, and literature was summarized in a table. Preterm birth rates at Ghent University Hospital, Ziekenhuis Oost-Limburg, and University Hospital Leuven in 2019 and 2020 were compared. Chi-square and Fisher's exact tests were used to compare PTB rates between 2019 and 2020, and Kaplan Meier survival analysis was used to compare pregnancy duration. The mean outcome measure was PTB incidence in 2020 (COVID-19) compared with PTB incidence in 2019 (pre-COVID-19).

RESULTS

Some (parts of) countries report decreases in PTB rates, others report no differences in incidence, and a minority of countries report an increased incidence of PTB. Almost all studies only consider live-births. In three tertiary care hospitals in Flanders, there were no differences in PTB rates before and during the COVID-19 pandemic.

CONCLUSION

The impact of the (mitigation measures during the) COVID-19 pandemic on PTB incidence is unclear and difficult to explore. To enable a correct interpretation, all conceptions before and during the pandemic should be taken into consideration, as well as all births, still or alive.

Changes in preterm birth and stillbirth during COVID-19 lockdowns in 26 countries

Preterm birth (PTB) is the leading cause of infant mortality worldwide. Changes in PTB rates, ranging from -90% to +30%, were reported in many countries following early COVID-19 pandemic response measures ('lockdowns'). It is unclear whether this variation reflects real differences in lockdown impacts, or perhaps differences in stillbirth rates and/or study designs. Here we present interrupted time series and meta-analyses using harmonized data from 52 million births in 26 countries, 18 of which had representative population-based data, with overall PTB rates ranging from 6% to 12% and stillbirth ranging from 2.5 to 10.5 per 1,000 births. We show small reductions in PTB in the first (odds ratio 0.96, 95% confidence interval 0.95-0.98, P value <0.0001), second (0.96, 0.92-0.99, 0.03) and third (0.97, 0.94-1.00, 0.09) months of lockdown, but not in the fourth month of lockdown (0.99, 0.96-1.01, 0.34), although there were some between-country differences after the first month. For high-income countries in this study, we did not observe an association between lockdown and stillbirths in the second (1.00, 0.88-1.14, 0.98), third (0.99, 0.88-1.12, 0.89) and fourth (1.01, 0.87-1.18, 0.86) months of lockdown, although we have imprecise estimates due to stillbirths being a relatively rare event. We did, however, find evidence of increased risk of stillbirth in the first month of lockdown in high-income countries (1.14, 1.02-1.29, 0.02) and, in Brazil, we found evidence for an association between lockdown and stillbirth in the second (1.09, 1.03-1.15, 0.002), third (1.10, 1.03-1.17, 0.003) and fourth (1.12, 1.05-1.19, <0.001) months of lockdown. With an estimated 14.8 million PTB annually worldwide, the modest reductions observed during early pandemic lockdowns translate into large numbers of PTB averted globally and warrant further research into causal pathways.

Impact of the COVID-19 Pandemic on Obstetric Interventions at a Public Hospital

INTRODUCTION

In response to the COVID-19 pandemic, health systems quickly implemented changes in care delivery with a goal of balancing patient-focused obstetric care with the need to protect pregnant persons and health care providers from infection. Yet, there is no consensus within the scientific community on the impact these measures have on obstetric outcomes in vulnerable populations. We aimed to assess the impact of the COVID-19 pandemic on rates of obstetric procedures and severe maternal morbidity (SMM) among births at an urban safety net institution.

METHODS

We used an interrupted time series design to calculate risk ratios (RRs) and 95% confidence intervals (CIs) comparing monthly rates of labor induction, cesarean births (overall and among nulliparous, term, singleton, vertex births), operative vaginal births, and SMM among births occurring at a public hospital before (March 1, 2016, to February 29, 2020) and during (March 1, 2020, to May 31, 2021) the COVID-19 pandemic.

RESULTS

There were 10,714 and 2,736 births in the prepandemic and postpandemic periods, respectively. Overall, the rates of obstetric interventions and SMM were constant over the two time periods. There were no significant differences in rates of labor induction (42% during prepandemic period vs. 45% during pandemic period; RR, 1.12; 95% CI, 0.93-1.34), operative vaginal births (5% vs. 6%; RR, 1.24; 95% CI, 0.88-1.76), cesarean births (28% vs. 33%; RR, 1.10; 95% CI, 0.94-1.28), or nulliparous, term, singleton, vertex cesarean births (24% vs. 31%; RR, 1.27; 95% CI, 0.92-1.74). Rates of SMM (7% vs. 8%; RR, 1.19; 95% CI, 0.86-1.65) were also unchanged.

CONCLUSIONS

Our findings indicate that the rapid implementation of measures to reduce viral transmission in the labor and delivery setting did not materially affect routine clinical management or rates of serious maternal complications.

Impact of the 1st Wave of the COVID-19 Pandemic and Lockdown on In Utero Transfer Activity in the Paris Area, France

Background: To assess changes in the number and profile of in utero transfer requests during the first lockdown. Methods: An observational, retrospective, cohort study. All pregnant women, from the Paris area (France), for whom a request for in utero transfer to the transfer unit was made during the first lockdown in France (from 17 March to 10 May 2020) or during a mirror period (years 2016 to 2019) were included. We compared the numbers and proportions of various indications for in utero transfer, the rates of in utero transfer acceptance and the proportion of outborn deliveries. Results: 206 transfer requests were made during the lockdown versus 227, 236, 204 and 228 in 2016, 2017, 2018 and 2019, respectively. The relative proportion of requests for threatened preterm births and for fetal growth restriction decreased from 45% in the mirror period to 37% and from 8 to 3%, respectively. The transfer acceptance rates and outborn deliveries did not differ between time periods. Conclusions: Although a reduction in in utero transfer requests was observed for certain indications, the first lockdown was not associated with a decrease in acceptance rates nor in an increase in outborn births of pregnancies with a high risk of prematurity in the Paris area.

COVID-19 pandemic and population-level pregnancy and neonatal outcomes in general population: A living systematic review and meta-analysis (Update#2: November 20, 2021)

INTRODUCTION

Conflicting reports of increases and decreases in rates of preterm birth (PTB) and stillbirth in the general population during the coronavirus disease 2019 (COVID-19) pandemic have surfaced. The objective of our study was to conduct a living systematic review and meta-analyses of studies reporting pregnancy and neonatal outcomes by comparing the pandemic and pre-pandemic periods.

MATERIAL AND METHODS

We searched the PubMed and Embase databases and reference lists of articles published up until November 20, 2021, and included English language studies that compared outcomes between the COVID-19 pandemic time period with pre-pandemic time periods. Risk of bias was assessed using the Newcastle-Ottawa scale. We conducted random-effects meta-analysis using the inverse variance method.

RESULTS

Fifty-two studies with low-to-moderate risk of bias, reporting on 2 372 521 pregnancies during the pandemic period and 28 518 300 pregnancies during the pre-pandemic period, were included. There was significant reduction in unadjusted estimates of PTB (43 studies, unadjusted odds ratio [uaOR] 0.95, 95% CI 0.93-0.98), but not in adjusted estimates (five studies, adjusted OR [aOR] 0.94, 95% CI 0.74-1.19). This reduction was noted in studies from single centers/health areas (29 studies, uaOR 0.90, 95% CI 0.85-0.94) but not in regional/national studies (14 studies, uaOR 0.99, 95% CI 0.99-1.01). There was reduction in spontaneous PTB (nine studies, uaOR 0.91, 95% CI 0.88-0.94) but not in induced PTB (eight studies, uaOR 0.90, 95% CI 0.79-1.01). There was no difference in the odds of stillbirth between the pandemic and pre-pandemic time periods (32 studies, uaOR 1.07, 95% CI 0.97-1.18 and three studies, aOR 1.18, 95% CI 0.86-1.63). There was an increase in mean birthweight during the pandemic period compared with the pre-pandemic period (nine studies, mean difference 21 g, 95% CI 13-30 g). The odds of maternal mortality were increased (five studies, uaOR 1.15, 95% CI 1.05-1.26); however, only unadjusted estimates were available, and the result was mostly influenced by one study from Mexico. There was significant publication bias for the outcome of PTB.

CONCLUSIONS

The COVID-19 pandemic may be associated with a reduction in PTB; however, referral bias cannot be excluded. There was no statistically significant difference in stillbirths between pandemic and pre-pandemic periods.

Assessment of Seasonality and Extremely Preterm Birth in Denmark

IMPORTANCE

Preterm birth, particularly extremely preterm birth, has been associated with substantial morbidity and mortality. Research during SARS-CoV-2-related lockdowns revealed reductions in the more severe subtypes of preterm birth in some countries, suggesting the presence of preventable risk factors, such as infectious diseases or social behavior. Seasonality may provide a similar means of assessing natural changes in the daily life of pregnant individuals that were similar to those experienced during the COVID-19 lockdown period.

OBJECTIVE

To evaluate the association between seasonality and extremely preterm birth.

DESIGN, SETTING, AND PARTICIPANTS

This nationwide cohort study included 1 136 143 pregnancies in Denmark with onset between January 1, 1997, and December 31, 2016, in which the fetuses survived 21 completed weeks of gestation. Pregnancies were followed up until preterm birth, fetal death, or 37 completed weeks of gestation. Data were analyzed from September 2020 to September 2021.

EXPOSURES

Season during gestation (primary exposure) and season of pregnancy onset.

MAIN OUTCOMES AND MEASURES

The main outcome of extremely preterm birth was defined as a live birth occurring between 22 weeks, 0 days' gestation and 27 weeks, 6 days' gestation. Cox regression analyses were used to estimate hazard ratios (HRs) for season during gestation and season of pregnancy onset, with adjustment for socioeconomic and demographic factors.

RESULTS

Among 662 338 pregnant individuals, the median age at pregnancy onset was 30.0 years (IQR, 6.0 years). Of 1 136 143 pregnancies, 2009 extremely preterm births (cumulative incidence, 0.18%) were identified during follow-up. Season during gestation was associated with extremely preterm birth, with cumulative incidences of 0.17% (95% CI, 0.16%-0.19%) in spring, 0.18% (95% CI, 0.17%-0.20%) in summer, 0.20% (95% CI, 0.18%-0.21%) in autumn, and 0.16% (95% CI, 0.14%-0.17%) in winter. Compared with winter, the adjusted HRs (AHRs) for the risk of extremely preterm birth were 1.11 (95% CI, 0.97-1.26) for spring, 1.15 (95% CI, 1.02-1.31) for summer, and 1.25 (95% CI, 1.10-1.42) for autumn. The number of extremely preterm births associated with the increased risk in the spring, summer, and autumn was 56.1 (95% CI, 18.2-99.7), representing 2.8% (95% CI, 0.9%-5.0%) of all extremely preterm births in the study. Season of pregnancy onset was not associated with the risk of extremely preterm birth in spring (AHR, 0.98; 95% CI, 0.95-1.01) or summer (AHR, 1.00; 95% CI, 0.96-1.03) compared with winter, but a slight increase in risk was observed in autumn (AHR, 1.05; 95% CI, 1.02-1.09) compared with winter.

CONCLUSIONS AND RELEVANCE

In this large, national cohort study, seasonality was associated with 2.8% of all extremely preterm births. Season during gestation was associated with the rate of extremely preterm birth, suggesting the presence of potential risk factors associated with season that may be preventable. Further research to identify risk factors for extremely preterm birth associated with seasonality is warranted.