Objective:

To investigate the impact of COVID-19 public health measures on perinatal outcomes including preterm birth, stillbirth, low birth weight, small for gestational age, caesarean delivery, breastfeeding initiation, and NICU admissions.

Approach:

• Study Design: Population-based study using linked administrative health databases comparing pregnancies before (January 2008–February 2020) and during (March 2020–March 2022) the pandemic.
• Data Analysis: Interrupted time series analyses using season-adjusted generalised linear models, stratified by income.

Key Findings:

• Preterm birth (PTB) rates increased from 8% prepandemic to 9.1% during the pandemic (19.0% relative increase, p<0.01).
• PTB rose by 27.1% in the lower-income group (8.8% to 10.1%, p=0.01) and by 19.7% in the higher income group (7.3% to 8.2%, p=0.02), though effect modification by income was statistically non-significant.
• Pregnancies fully exposed during the first and second year of the pandemic experienced higher rates of PTB by 15.0% (p=0.01) and 11.6% (p<0.01), respectively.
• No changes in stillbirth (0.7‰ vs 0.61%; p=0.37) or NICU admission rates (8.3% vs 8.2%; p=0.69) were observed.
• Low birth weight (LBW) rates increased from 5.5% to 6.3% (13.9% relative increase, p=0.05).
• Caesarean delivery rates increased by 24.6% during the first year of the pandemic (p<0.01).
• Breastfeeding initiation rates decreased from 82.5% to 81.8% (3.9% relative decrease, p=0.01) but showed a slight increase during the pandemic period (p=0.02).

Interpretation:

The COVID-19 pandemic measures were associated with increased rates of preterm birth and caesarean deliveries, particularly among pregnancies fully exposed to pandemic measures.

Limitations:

• The study relied on administrative health databases, which may not capture all relevant clinical data.
• Effect modification by income was not statistically significant despite observed differences.

Conclusion:

Longer exposure to pandemic-related disruptions is linked to higher rates of preterm birth and caesarean delivery, while stillbirth, NICU admissions, and breastfeeding initiation rates remained stable over the pandemic period.