Researchers found that COVID-19 lockdowns were linked to a 4% drop in pre-term births in Europe and Australia and a 37% rise in antenatal depression screenings. However, most other birth outcomes and health disparities showed no significant change due to the limited data available.

Study: The association of COVID-19 lockdowns with adverse birth and pregnancy outcomes in 28 high-income countries: a systematic review and meta-analysis. Image Credit: Corona Borealis Studio / Shutterstock

In a recent review published in the journal Nature Human Behaviour, researchers conducted a systematic review and meta-analysis to investigate the impact of COVID-19 lockdowns on adverse birth and pregnancy outcomes (ABPOs) during the pandemic. The review focused on publications comparing these impacts in high-income countries (HICs) between January 2019 and June 2023, both before and during the pandemic.

A random-effects meta-analysis of 132 studies revealed that the first lockdown significantly reduced pre-term birth rates (specifically spontaneous pre-term births) in Europe and Australia, and increased positive depression antenatal screening rates. The analysis also identified an 18% decrease in neonatal mortality associated with lockdown. However, this finding should be interpreted with caution due to the strong influence of a single extensive study and the need for further time-adjusted analysis. While the study also attempted to elucidate inequalities between regions, ethnic groups, and deprivation levels, insufficient data prevented these analyses and underscored the need for further research on the topic.

Background

The coronavirus disease 2019 (COVID-19) pandemic prompted several governments to impose social distancing measures, known as ‘lockdowns’, to mitigate disease transmission and curb infection rates. Research during these non-pharmaceutical interventions suggests that these lockdowns may have inadvertently triggered alterations in adverse birth and pregnancy outcomes (ABPOs), specifically, exacerbated stillbirth rates in low- to middle-income countries (LMICs) and reductions in pre-term birth (PTB) rates in high-income countries (HICs).

Previous examinations of these trends have highlighted substantial regional differences between LMICs and HICs, which may be attributed to variations in the stringency of national lockdown policies, disparities in healthcare systems, and COVID-19 epidemiology, including infection rates and testing. Even within HICs, healthcare access and socioeconomic disparities between different ethnic groups and deprivation cohorts are expected to have resulted in a spectrum of ABPO outcomes, but prior studies have provided conflicting findings.

About the study

The present review aims to address these inconsistencies in the literature by collating, synthesizing, and reanalyzing data from publications that evaluate the association between COVID-19 lockdowns and ABPO outcomes. It focuses on HICs and further investigates if variations in continental regions, ethnic groups, time periods (first versus subsequent lockdowns), and deprivation levels altered ABPO outcomes during and shortly after the pandemic.

Publications for study inclusion were obtained through a custom search of three online scientific repositories: EMBASE, Web of Science, and MEDLINE/PubMed. Additionally, preprints (MedRxiv) and unpublished reports were manually obtained.

The search and subsequent screening process conforms to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was registered on the PROSPERO registry. The inclusion criteria comprised: 1. COVID-19 lockdown (intervention), and 2. ABPO outcomes, and 3. HICs derived population (except Sweden, which did not enforce a lockdown). Potential publications were screened via a cascade of title and abstract screening, duplicate removal, and full-text screening.

Study data was extracted using a custom tool developed in Microsoft Excel and included: 1. study characteristics (total births and outcomes), 2. deprivation, and 3. ethnicity. Missing data were obtained through personal emails to study authors or proxy estimates (when authors did not respond).

Meta-analyses were conducted for variables of interest with at least three corresponding studies. Outcomes were analyzed using random-effects models adjusted for heterogeneity and continent (region). Subgroup analyses were undertaken where applicable (e.g., for studies reporting outcomes from second or subsequent lockdowns). Deprivation was estimated using the Area Deprivation Composite Index scores.

Study findings

The initial custom search strategy identified 14,215 records (titles) that met the eligibility criteria. Deduplication narrowed this down to 9,780. Full-text screening identified 207 eligible studies. Studies with overlapping populations, time periods, or outcomes were excluded from the meta-analyses, resulting in a final study dataset of 132. Summary statistics revealed that these studies included participants from 28 countries, with Europe (45%) and North America (41%) comprising the bulk. Cohort studies were the most common (86%), followed by cross-sectional publications (11%).

Meta-analyses revealed that pre-term births (PTBs) significantly declined (-4%, specifically spontaneous PTBs) during lockdown periods. This finding remained robust even after adjusting for long-term trends (11 studies, -3%), but was found to be limited to the first lockdown. Notably, high inter-study heterogeneity and subsequent subgroup analyses revealed that these findings were significant only for European and Australian continental regions and not for North America, Asia, South America, or the Middle East.

Analyses of stillbirth data did not find any credible evidence of an association between pre-COVID-19 and COVID-19 lockdown periods. While 18 studies explicitly tested for low birth weight (LBW), no credible evidence supporting an association was observed. For other outcomes, the overall pooled analyses showed no significant association for caesarean sections or sepsis (based on limited studies). However, substantial regional variations were observed despite no overall association for:

• Neonatal admissions: A decrease was observed in the Middle East during lockdown, while an increase was noted in Asia.
• Maternal readmission: A decrease was observed in maternal readmission rates following lockdowns in Europe, specifically in the UK.

Neonatal mortality was associated with an 18% decrease during lockdown (RR 0.82, 95% CI 0.74–0.91); however, the researchers noted that this pooled estimate requires cautious interpretation and further time-adjusted investigation.

The only other significant overall finding was the increase in antenatal depression screening rates, which were observed to rise by 37%. Unfortunately, inequality-based analyses could not be undertaken due to insufficient data availability, characterized by high inter-study heterogeneity and limited data for subgroup analyses.

Conclusions

The present meta-analysis revealed a reduction in spontaneous pre-term births (in Europe and Australia) and an increase in positive antenatal screening for depression following the implementation of COVID-19-associated lockdown restrictions. The study also found a decrease in neonatal mortality, though this needs further confirmation, and highlighted significant regional differences in neonatal admissions and maternal readmissions. They further highlight a lack of sufficient data on the impacts of inequalities on these trends, underscoring the need for further research in the field.

The authors suggest that COVID-19 lockdowns served as a natural experiment, and the uneven associations observed require further exploration, potentially through mixed-methods research, to understand the underlying health determinants and barriers to care. These findings indicate that broad, umbrella lockdown approaches can have unequal consequences, suggesting that targeted policies and tailored support structures are necessary to better promote maternal and neonatal health.