Preterm birth after the introduction of COVID-19 mitigation measures in Norway, Sweden, and Denmark: a registry-based difference-in-differences study

Changes in stillbirths and child and youth mortality in 2020 and 2021 during the COVID-19 pandemic

BACKGROUND

The COVID-19 pandemic has been extensively studied for its impact on mortality, particularly in older age groups. However, the pandemic effects on stillbirths and mortality rates in neonates, infants, children and youth remain poorly understood. This study comprehensively analyses the pandemic influence on young mortality and stillbirths across 112 countries and territories in 2020 and 104 in 2021.

METHODS

Using data from civil registers and vital statistics systems (CRVS) and the Health Management Information System (HMIS), we estimate expected mortality levels in a non-pandemic setting and relative mortality changes (p-scores) through generalized linear models. The analysis focuses on the distribution of country-specific mortality changes and the proportion of countries experiencing deficits, no changes and excess mortality in each age group.

RESULTS

Results show that stillbirths and under-25 mortality were as expected in most countries during 2020 and 2021. However, among countries with changes, more experienced deficits than excess mortality, except for stillbirths, neonates and those aged 10-24 in 2021, where, despite the predominance of no changes, excess mortality prevailed. Notably, a fifth of examined countries saw increases in stillbirths and a quarter in young adult mortality (20-24) in 2021. Our findings are highly consistent between females and males and similar across income levels.

CONCLUSION

Despite global disruptions to essential services, stillbirths and youth mortality were as expected in most observed countries, challenging initial hypotheses. However, the study suggests the possibility of delayed adverse effects that require more time to manifest at the population level. Understanding the lasting impacts of the COVID-19 pandemic requires ongoing, long-term monitoring of health and deaths among children and youth, particularly in low- and lower-middle-income countries.

The Incidence of Necrotizing Enterocolitis and Late-Onset Sepsis during the COVID-19 Pandemic in Sweden: A Population-Based Cohort Study

INTRODUCTION

The effect of the pandemic restrictions in the NICUs is not well studied. Necrotizing enterocolitis (NEC) is characterized by intestinal inflammation and bacterial invasion. This study aimed to investigate whether the incidence of NEC has changed during the COVID-19 pandemic in Sweden and whether it was associated with a change in the frequency of extremely preterm births.

METHODS

Data were retrieved from the Swedish Neonatal Quality Register (SNQ) for infants registered between January 2017 and December 2021 born below a gestational age of 35 weeks. The registry completeness is 98-99%. The diagnosis of NEC was the primary outcome. Generalized linear model analysis was used to calculate the risk ratio for NEC.

RESULTS

Totally 13,239 infants were included. 235 (1.8%) infants developed NEC, out of which 91 required surgical treatment. 8,967 infants were born before COVID-19 pandemic and 4,272 during. Median gestational age at birth was 32.8 weeks in both periods. The incidence of NEC was significantly lower during COVID-19 pandemic compared to the prior period (1.43 vs. 1.94%, p 0.037), but not the incidence of surgical NEC. The crude risk ratio of developing NEC during COVID-19 pandemic was 0.74 (95% CI: 0.55-0.98). The incidence of late-onset sepsis with positive culture was also declined during COVID-19 (3.21 vs. 4.15%, p value 0.008).

CONCLUSION

While we found significant reduction in the incidence of NEC and culture-positive late-onset sepsis during the COVID-19 pandemic, the number of extremely preterm births was unchanged.

Impact of COVID-19 on Perinatal Outcomes and Birth Locations in a Large US Metropolitan Area

This was a population-based study to determine the impact of COVID-19 on birth outcomes in the Chicago metropolitan area, comparing pre-pandemic (April-September 2019) versus pandemic (April-September 2020) births. Multivariable regression models that adjusted for demographic and neighborhood characteristics were used to estimate the marginal effects of COVID-19 on intrauterine fetal demise (IUFD)/stillbirth, preterm birth, birth hospital designation, and maternal and infant hospital length of stay (LOS). There were no differences in IUFD/stillbirths or preterm births between eras. Commercially insured preterm and term infants were 4.8 percentage points (2.3, 7.4) and 3.4 percentage points (2.5, 4.2) more likely to be born in an academic medical center during the pandemic, while Medicaid-insured preterm and term infants were 3.6 percentage points less likely (-6.5, -0.7) and 1.8 percentage points less likely (-2.8, -0.9) to be born in an academic medical center compared to the pre-pandemic era. Infant LOS decreased from 2.4 to 2.2 days (-0.35, -0.20), maternal LOS for indicated PTBs decreased from 5.6 to 5.0 days (-0.94, -0.19), and term births decreased from 2.5 to 2.3 days (-0.21, -0.17). The pandemic had a significant effect on the location of births that may have exacerbated health inequities that continue into childhood.

The impact of non-pharmaceutical interventions on premature births during the COVID-19 pandemic: a nationwide observational study in Korea

Background

Non-pharmaceutical interventions (NPIs), such as social distancing and hand washing, have been associated with a decline in the preterm birth rate worldwide. We aimed to evaluate whether the preterm birth rate in Korea during the coronavirus disease 2019 lockdown has changed compared to that in previous years.

Method

A birth registry from the Korea Statistical Information Service, which is a nationwide official database, was used to include all births claimed to have occurred between 2011 and 2020. Newborns with gestational age (GA) less than 22 weeks and birth weight less than 220 g were excluded. The pre-NPI period was designated as January 2011 to January 2020, and the NPI period was defined as February 2020 to December 2020. We assessed the effect of NPI on the incidence of prematurity per 100 births using an interrupted time-series quasi-experimental design and implementing an autoregressive integrated moving average (ARIMA) model.

Results

From 2011 to 2020, a total of 3,931,974 live births were registered, among which 11,416 were excluded. Consequently, the final study population included 3,920,558 live births (both singleton and multiple births) among which 275,009 (7.0%) were preterm. The preterm birth rate was significantly higher during the NPI period (8.68%) compared to that in the pre-NPI period (6.92%) (P < 0.001). The ARIMA model showed that in all singleton and multiple births, except those in July (observed 9.24, expected 8.54, [95% prediction interval {PI} 8.13-8.96], percent difference 7.81%), September (observed 7.89, expected 8.35, [95% PI 7.93-8.76], percent difference -5.66%), and December (observed 9.90, expected 9.40, [95% PI 8.98-9.82], percent difference 5.2%), most observed values were within the 95% PI of the expected values and showed an increasing trend.

Conclusion

In this nationwide observational study, the trend in premature birth rate did not significantly change due to NPI implementation in Korea, as it had been increasing since 2011. The trend of Korea's birth rate appears to be unaffected by the implementation of NPIs; however, further studies with a longer follow-up period are needed.

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.

Indirect effects of the COVID-19 pandemic on risk of gestational diabetes and factors contributing to increased risk in a multiethnic population: a retrospective cohort study

BACKGROUND

The COVID-19 pandemic has had indirect effects on pregnancy outcomes. There is limited data on the impact on gestational diabetes (GDM) in diverse populations and the possible underlying mediators. This study aimed to assess the risk of GDM pre-COVID-19 and in two distinct pandemic exposure periods, and to determine the potential factors contributing to increased risk in a multiethnic population.

METHODS

A multicentre, retrospective cohort study was performed of women with singleton pregnancy receiving antenatal care at three hospitals two years pre-COVID-19 (January 2018 - January 2020), first year of COVID-19 with limited pandemic-mitigating restrictions (February 2020 - January 2021) and second year of COVID-19 with stringent restrictions (February 2021 - January 2022). Baseline maternal characteristics and gestational weight gain (GWG) were compared between cohorts. The primary outcome was GDM, assessed using univariate and multivariate generalised estimating equations models.

RESULTS

28,207 pregnancies met the inclusion criteria, 14,663 pregnancies two years pre-COVID-19, 6,890 in COVID-19 Year 1 and 6,654 in COVID-19 Year 2. Maternal age increased across exposure periods (30.7 ± 5.0 years pre-COVID-19 vs 31.0 ± 5.0 years COVID-19 Year 1 vs 31.3 ± 5 years COVID-19 Year 2; p < 0.001). There were increases in pre-pregnancy body mass index (BMI) (25.5 ± 5.7 kg/m² vs 25.7 ± 5.6 kg/m² vs 26.1 ± 5.7 kg/m²; p < 0.001), proportion who were obese (17.5% vs 18.1% vs 20.7%; p < 0.001) and proportion with other traditional risk factors for GDM including South Asian ethnicity and prior history of GDM. Rate of GWG and proportion exceeding recommended GWG increased with pandemic exposure (64.3% vs 66.0% vs 66.6%; p = 0.009). GDM diagnosis increased across exposure periods (21.2% vs 22.9% vs 24.8%; p < 0.001). Both pandemic exposure periods were associated with increased risk of GDM on univariate analysis, only COVID-19 Year 2 remaining significantly associated after adjusting for maternal baseline characteristics and GWG (OR 1.17 [1.06, 1.28], p = 0.01).

CONCLUSIONS

Diagnosis of GDM increased with pandemic exposure. Progressive sociodemographic changes and greater GWG may have contributed to increased risk. However, exposure to the second year of COVID-19 remained independently associated with GDM after adjusting for shifts in maternal characteristics and GWG.

Preterm birth in the Nordic countries-Capacity, management and outcome in neonatal care

AIM

Organisation of care, perinatal and neonatal management of very preterm infants in the Nordic regions were hypothesised to vary significantly. The aim of this observational study was to test this hypothesis.

METHODS

Information on preterm infants in the 21 greater healthcare regions of Denmark, Finland, Iceland, Norway and Sweden was gathered from national registers in 2021. Preterm birth rates, case-mix, perinatal interventions, neonatal morbidity and survival to hospital discharge in very (<32 weeks) and extremely preterm infants (<28 weeks of gestational age) were compared.

RESULTS

Out of 287 642 infants born alive, 16 567 (5.8%) were preterm, 2389 (0.83%) very preterm and 800 (0.28%) were extremely preterm. In very preterm infants, exposure to antenatal corticosteroids varied from 85% to 98%, live births occurring at regional centres from 48% to 100%, surfactant treatment from 28% to 69% and use of mechanical ventilation varied from 13% to 77% (p < 0.05 for all comparisons). Significant regional variations within and between countries were also seen in capacity in neonatal care, case-mix and number of admissions, whereas there were no statistically significant differences in survival or major neonatal morbidities.

CONCLUSION

Management of very preterm infants exhibited significant regional variations in the Nordic countries.

Patterns of Prenatal Care Delivery and Obstetric Outcomes before and during the COVID-19 Pandemic

OBJECTIVE

 Health care providers and health systems confronted new challenges to deliver timely, high-quality prenatal care during the coronavirus disease 2019 (COVID-19) pandemic as the pandemic raised concerns that care would be delayed or substantively changed. This study describes trends in prenatal care delivery in 2020 compared with 2018 to 2019 in a large, commercially insured population and investigates changes in obstetric care processes and outcomes.

STUDY DESIGN

 This retrospective cohort study uses de-identified administrative claims for commercially insured patients. Patients whose entire pregnancy took place from March 1 to December 31 in years 2018, 2019, and 2020 were included. Trends in prenatal care, including in-person, virtual, and emergency department visits, were evaluated, as were prenatal ultrasounds. The primary outcome was severe maternal morbidity (SMM). Secondary outcomes included preterm birth and stillbirth. To determine whether COVID-19 pandemic-related changes in prenatal care had an impact on maternal outcomes, we compared the outcome rates during the pandemic period in 2020 to equivalent periods in 2018 and 2019.

RESULTS

 In total, 35,112 patients were included in the study. There was a significant increase in the prevalence of telehealth visits, from 1.1 to 1.2% prior to the pandemic to 17.2% in 2020, as well as a significant decrease in patients who had at least one emergency department visit during 2020. Overall prenatal care and ultrasound utilization were unchanged. The rate of SMM across this period was stable (2.3-2.8%) with a statistically significant decrease in the preterm birth rate in 2020 (7.4%) compared with previous years (8.2-8.6%; p < 0.05) and an unchanged stillbirth rate was observed.

CONCLUSION

 At a time when many fields of health care were reshaped during the pandemic, these observations reveal considerable resiliency in both the processes and outcomes of obstetric care.

KEY POINTS

· Overall prenatal care and ultrasound were unchanged from 2018 to 2019 to 2020.. · There was a large increase in the prevalence of telehealth visits in 2020.. · There was no change in the rate of severe maternal morbidity or stillbirth in 2020 compared with 2018 to 2019..

Impacts of COVID-19 pandemic on preterm birth: a systematic review and meta-analysis

OBJECTIVES

The COVID-19 pandemic has significantly affected healthcare systems and daily well-being. However, the reports of the indirect impacts of the pandemic on preterm birth remain conflicting. We performed a meta-analysis to examine whether the pandemic altered the risk of preterm birth.

STUDY DESIGN

This was a systematic review and meta-analysis of the previous literature.

METHODS

We searched MEDLINE and Embase databases until March 2022 using appropriate keywords and extracted 63 eligible studies that compared preterm between the COVID-19 pandemic period and the prepandemic period. A random effects model was used to obtain the pooled odds of each outcome. The study protocol was registered with PROSPERO (No. CRD42022326717).

RESULTS

The search identified 3827 studies, of which 63 reports were included. A total of 3,220,370 pregnancies during the COVID-19 pandemic period and 6,122,615 pregnancies during the prepandemic period were studied. Compared with the prepandemic period, we identified a significant decreased odds of preterm birth (PTB; <37 weeks' gestation; pooled odds ratio [OR; 95% confidence interval (CI)] = 0.96 [0.94, 0.98]; I² = 78.7%; 62 studies) and extremely PTB (<28 weeks' gestation; pooled OR [95% CI] = 0.92 [0.87, 0.97]; I² = 26.4%; 25 studies) during the pandemic, whereas there was only a borderline significant reduction in the odds of very PTB (<32 weeks' gestation; pooled OR [95% CI] = 0.93 [0.86, 1.01]; I² = 90.1%; 33 studies) between the two periods. There was significant publication bias for PTB.

CONCLUSION

Pooled results suggested the COVID-19 pandemic was associated with preterm birth, although there was only a borderline significant reduction for very PTB during the pandemic compared with the prepandemic period. Large studies showed conflicting results, and further research on whether the change is related to pandemic mitigation measures was warranted.

Impact of COVID-19 on pregnancy-related healthcare utilisation: a prospective nationwide registry study

OBJECTIVE

To assess the impact of COVID-19 on pregnancy-related healthcare utilisation and differences across social groups.

DESIGN

Nationwide longitudinal prospective registry-based study.

SETTING

Norway.

PARTICIPANTS

Female residents aged 15-50 years (n=1 244 560).

MAIN OUTCOME MEASURES

Pregnancy-related inpatient, outpatient and primary care healthcare utilisation before the COVID-19 pandemic (prepandemic: 1 January to 11 March 2020), during the initial lockdown (first wave: 12 March to 3 April 2020), during the summer months of low restrictions (summer period: 4 April to 31 August 2020) and during the second wave to the end of the year (second wave: 1 September to 31 December 2020). Rates were compared with the same time periods in 2019.

RESULTS

There were 130 924 inpatient specialist care admissions, 266 015 outpatient specialist care consultations and 2 309 047 primary care consultations with pregnancy-related diagnostic codes during 2019 and 2020. After adjusting for time trends and cofactors, inpatient admissions were reduced by 9% (adjusted incidence rate ratio (aIRR)=0.91, 95% CI 0.87 to 0.95), outpatient consultations by 17% (aIRR=0.83, 95% CI 0.71 to 0.86) and primary care consultations by 10% (aIRR=0.90, 95% CI 0.89 to 0.91) during the first wave. Inpatient care remained 3%-4% below prepandemic levels throughout 2020. Reductions according to education, income and immigrant background were also observed. Notably, women born in Asia, Africa or Latin America had a greater reduction in inpatient (aIRR=0.87, 95% CI 0.77 to 0.97) and outpatient (aIRR 0.90, 95% CI 0.86 to 0.95) care during the first wave, compared with Norwegian-born women. We also observed that women with low education had a greater reduction in inpatient care during summer period (aIRR=0.88, 95% CI 0.83 to 0.92), compared with women with high educational attainment.

CONCLUSION

Following the introduction of COVID-19 mitigation measures in Norway in March 2020, there were substantial reductions in pregnancy-related healthcare utilisation, especially during the initial lockdown and among women with an immigrant background.

Changes in preterm birth and birthweight during the SARS-CoV-2 pandemic: a nationwide study in South Korea

Birthweight is a strong determinant of a neonate’s health. The SARS-CoV-2 pandemic’s impact on birthweight has not been investigated in-depth, with inconsistent conclusions from initial studies. To assess changes in preterm birth and inappropriate birthweight between the SARS-CoV-2 pandemic and pre-pandemic periods. A nationwide birth micro-data consisted with exhaustive census of all births in 2011–2020 in South Korea was accessed to examine whether the mean birthweight and rates of under/overweight births changed significantly during the SARS-CoV-2 pandemic year (2020) compared to those of the pre-pandemic period (2011–2019). A total of 3,736,447 singleton births were analyzed. Preterm birth was defined as < 37 weeks of gestation. Low birthweight (LBW) and macrosomia were defined as birthweights < 2.5 kg and ≥ 4.0 kg, respectively. Small for gestational age (SGA) and large for gestational age (LGA) were defined as birthweights below the 10th and above 90th percentiles for sex and gestational age, respectively. Inappropriate birthweight was defined as one or more LBW, macrosomia, SGA, or LGA. Generalized linear models predicted birth outcomes and were adjusted for parental age and education level, marital status, parity, gestational age, and months from January 2011. There were 3,481,423 and 255,024 singleton births during the pre-pandemic and pandemic periods, respectively. Multivariable generalized linear models estimated negative associations between the pandemic and preterm birth (odds ratio [OR], 0.968; 95% confidence interval [CI] 0.958–0.978), LBW (OR: 0.967, 95% CI 0.956–0.979), macrosomia (OR: 0.899, 95% CI 0.886–0.912), SGA (OR: 0.974, 95% CI 0.964–0.983), LGA (OR: 0.952, 95% CI 0.945–0.959), and inappropriate birthweight (OR: 0.958, 95% CI 0.952–0.963), indicating a decline during the pandemic compared to pre-pandemic period. An 8.98 g decrease in birthweight (95% CI 7.98–9.99) was estimated during the pandemic. This is the largest and comprehensive nationwide study to date on the impact of the SARS-CoV-2 pandemic on preterm birth and inappropriate birthweight. Birth during the pandemic was associated with lower odds of being preterm, underweight, and overweight. Further studies are required to understand the dynamics underlying this phenomenon.

Limited Effects of SARS-CoV-2 Pandemic-related Lockdowns and Reduced Population Mobility on Preterm Birth Rates: A Secondary Analysis of Bavarian Obstetric Quality Parameters from 2010 to 2020

Introduction International studies on preterm birth rates during COVID-19 lockdowns report different results. This study examines preterm birth rates during lockdown periods and the impact of the mobility changes of the population in Bavaria, Germany.

Material and Methods This is a secondary analysis of centrally collected data on preterm births in Bavaria from 2010 to 2020. Preterm births (< 37 weeks) in singleton and twin pregnancies during two lockdowns were compared with corresponding periods in 2010 – 2019. Fisherʼs exact test was used to compare raw prevalence between groups. Potential effects of two fixed lockdown periods and of variable changes in population mobility on preterm birth rates in 2020 were examined using additive logistic regression models, adjusting for long-term and seasonal trends.

Results Unadjusted preterm birth rates in 2020 were significantly lower for singleton pregnancies during the two lockdown periods (Lockdown 1: 5.71% vs. 6.41%; OR 0.88; p < 0.001; Lockdown 2: 5.71% vs. 6.60%; OR = 0.86; p < 0.001). However, these effects could not be confirmed after adjusting for long-term trends (Lockdown 1: adj. OR = 0.99; p = 0.73; Lockdown 2: adj. OR = 0.96; p = 0.24). For twin pregnancies, differences during lockdown were less marked (Lockdown 1: 52.99% vs. 56.26%; OR = 0.88; p = 0.15; Lockdown 2: 58.06% vs. 58.91%; OR = 0.97; p = 0.70). Reduced population mobility had no significant impact on preterm birth rates in singleton pregnancies (p = 0.14) but did have an impact on twin pregnancies (p = 0.02).

Conclusions Reduced preterm birth rates during both lockdown periods in 2020 were observed for singleton and twin pregnancies. However, these effects are reduced when adjusting for long-term and seasonal trends. Reduced population mobility was associated with lower preterm birth rates in twin pregnancies.

Preterm birth rates were slightly lower in Denmark during the first year of the COVID-19 pandemic compared with the previous 4 years

Aim

Our aim was to investigate the rates of preterm births, live births and stillbirths in Denmark during the first year of the COVID‐19 pandemic.

Methods

This was a national, cross‐sectional registry‐based study that used the Danish Newborn Quality database, which covers all births in Denmark. The proportions of preterm births were compared between the COVID‐19 pandemic period of 1 March 2020 to 28 February 2021 and the preceding 4‐year pre‐pandemic period.

Results

We studied 60 323 and 244 481 newborn infants from the pandemic and pre‐pandemic periods, respectively. The proportion of preterm live births and stillbirths declined slightly, from 6.29% during the pre‐pandemic period to 6.02% during the pandemic period. This corresponded to a relative risk (RR) of 0.96, with a 95% confidence interval (CI) of 0.93–0.99 during the pandemic. The RRs for extremely preterm, very preterm and moderately preterm infants were 0.88 (95% CI 0.76–1.02), 0.91 (95% CI 0.82–1.02) and 0.97 (95% CI 0.93–1.01), respectively.

Conclusion

This comparative study showed a small reduction in just over 4%, from 6.29 to 6.02% in the proportion of all preterm births during the pandemic period, compared with the previous four pandemic‐free years. There were no differences between subcategories of preterm births.

Increase in preterm stillbirths in association with reduction in iatrogenic preterm births during COVID-19 lockdown in Australia: a multicenter cohort study

Background

The COVID-19 pandemic has been associated with a worsening of perinatal outcomes in many regions around the world. Melbourne, Australia, had one of the longest and most stringent lockdowns worldwide in 2020 while recording only rare instances of COVID-19 infection in pregnant women.

Objective

This study aimed to compare the stillbirth and preterm birth rates in women who were exposed or unexposed to lockdown restrictions during pregnancy.

Study Design

This was a retrospective, multicenter cohort study of perinatal outcomes in Melbourne before and during the COVID-19 lockdown. The lockdown period was defined as the period from March 23, 2020 to March 14, 2021. Routinely-collected maternity data on singleton pregnancies ≥24 weeks gestation without congenital anomalies were obtained from all the 12 public hospitals in Melbourne. We defined the lockdown-exposed cohort as those women for whom weeks 20 to 40 of gestation occurred during the lockdown and the unexposed control group as women from the corresponding calendar periods 12 and 24 months before. The main outcome measures were stillbirth, preterm birth, fetal growth restriction (birthweight < third centile), and iatrogenic preterm birth for fetal compromise. We performed multivariable logistic regression analysis to compare the odds of stillbirth, preterm birth, fetal growth restriction, and iatrogenic preterm birth for fetal compromise, adjusting for multiple covariates.

Results

There were 24,817 births in the exposed group and 50,017 births in the control group. There was a significantly higher risk of preterm stillbirth in the exposed group than the control group (0.26% vs 0.18%; adjusted odds ratio, 1.49; 95% confidence interval, 1.08–2.05; P=.015). There was also a significant reduction in the preterm birth of live infants <37 weeks (5.68% vs 6.07%; adjusted odds ratio, 0.93; 95% confidence interval, 0.87–0.99; P=.02), which was largely mediated by a significant reduction in iatrogenic preterm birth (3.01% vs 3.27%; adjusted odds ratio, 0.91; 95% confidence interval, 0.83–0.99; P=.03), including iatrogenic preterm birth for fetal compromise (1.25% vs 1.51%; adjusted odds ratio, 0.82; 95% confidence interval, 0.71–0.93; P=.003). There were also significant reductions in special care nursery admissions during lockdown (11.53% vs 12.51%; adjusted odds ratio, 0.90; 95% confidence interval, 0.86–0.95; P<.0001). There was a trend to fewer spontaneous preterm births <37 weeks in the exposed group of a similar magnitude to that reported in other countries (2.69% vs 2.82%; adjusted odds ratio, 0.95; 95% confidence interval, 0.87–1.05; P=.32).

Conclusion

Lockdown restrictions in Melbourne, Australia were associated with a significant reduction in iatrogenic preterm birth for fetal compromise and a significant increase in preterm stillbirths. This raises concerns that pandemic conditions in 2020 may have led to a failure to identify and appropriately care for pregnant women at an increased risk of antepartum stillbirth. Further research is required to understand the relationship between these 2 findings and to inform our ongoing responses to the pandemic.