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

Abstract

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.

Zusammenfassung

Einleitung Internationale Studien zu Frühgeburtenraten während den COVID-19-Lockdowns kommen zu unterschiedlichen Ergebnissen. Diese Studie untersucht die Frühgeburtenraten während den Lockdowns sowie die Auswirkungen von Änderungen der Bevölkerungsmobilität in Bayern auf die Frühgeburtenraten.

Material und Methoden Es handelt sich um eine Sekundäranalyse von zentral erhobenen Daten zu Frühgeburten in Bayern zwischen 2010 und 2020. Die Frühgeburten (< 37. Schwangerschaftswoche) bei Einlings- und Zwillingsschwangerschaften, die in der Zeit der beiden Lockdowns auftraten, wurden den Frühgeburten in den Vergleichszeiträume der Jahre 2010 – 2019 gegenübergestellt. Die Rohprävalenzen der Gruppen wurden mit dem exakten Test nach Fisher verglichen. Additive logistische Regressionsmodelle wurden eingesetzt, um die potenziellen Auswirkungen von 2 Lockdowns sowie von Änderungen der Bevölkerungsmobilität auf die Frühgeburtenraten im Jahre 2020 zu untersuchen. Die Effekte wurden dann zusätzlich auf langfristige und saisonbedingte Trends adjustiert.

Ergebnisse Die unbereinigten Frühgeburtenraten von Einlingsschwangerschaften während den 2 Lockdowns im Jahre 2020 waren signifikant niedriger (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). Nachdem die Effekte auf langfristige und saisonbedingte Trends adjustiert worden waren, konnten die Auswirkungen aber nicht bestätigt werden (Lockdown 1: ber. OR = 0,99; p = 0,73; Lockdown 2: ber. OR = 0,96; p = 0,24). Die Unterschiede während der Lockdownzeiträume waren bei Zwillingsschwangerschaften weniger ausgeprägt (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). Eine geringere Bevölkerungsmobilität hatte keine signifikanten Auswirkungen auf die Frühgeburtenraten bei Einlingsschwangerschaften (p = 0,14), dafür aber auf die Frühgeburtenraten bei Zwillingsschwangerschaften (p = 0,02).

Schlussfolgerungen Es wurden niedrigere Frühgeburtenraten bei Einlings- und Zwillingsschwangerschaften während den beiden Lockdowns im Jahre 2020 beobachtet. Diese Effekte wurden teilweise gemindert, wenn sie auf langfristige und saisonale Trends adjustiert wurden. Die geringere Bevölkerungsmobilität war mit einer niedrigeren Frühgeburtenrate bei Zwillingsschwangerschaften assoziiert.

Key words

COVID-19 - SARS-CoV-2 - preterm birth - lockdown measures - preterm delivery

Schlüsselwörter

COVID-19 - SARS-CoV-2 - Frühgeburt - Lockdown-Maßnahmen

^* Joint senior authors.

Publication History

Received: 04 April 2022

Accepted after revision: 19 May 2022

Article published online:
15 July 2022

• References

• 1 Stumpfe FM, Titzmann A, Schneider MO. et al. SARS-CoV-2 Infection in Pregnancy – a Review of the Current Literature and Possible Impact on Maternal and Neonatal Outcome. Geburtshilfe Frauenheilkd 2020; 80: 380-390
• 2 Hein A, Kehl S, Haberle L. et al. Prevalence of SARS-CoV-2 in Pregnant Women Assessed by RT-PCR in Franconia, Germany: First Results of the SCENARIO Study (SARS-CoV-2 prEvalence in pregNAncy and at biRth In FrancOnia). Geburtshilfe Frauenheilkd 2022; 82: 226-234
• 3 De Curtis M, Villani L, Polo A. Increase of stillbirth and decrease of late preterm infants during the COVID-19 pandemic lockdown. Arch Dis Child Fetal Neonatal Ed 2020;
• 4 Kc A, Gurung R, Kinney MV. et al. Effect of the COVID-19 pandemic response on intrapartum care, stillbirth, and neonatal mortality outcomes in Nepal: a prospective observational study. Lancet Glob Health 2020; 8: e1273-e1281
• 5 Khalil A, von Dadelszen P, Draycott T. et al. Change in the Incidence of Stillbirth and Preterm Delivery During the COVID-19 Pandemic. JAMA 2020;
• 6 Hedermann G, Hedley PL, Baekvad-Hansen M. et al. Danish premature birth rates during the COVID-19 lockdown. Arch Dis Child Fetal Neonatal Ed 2021; 106: 93-95
• 7 Philip RK, Purtill H, Reidy E. et al. Unprecedented reduction in births of very low birthweight (VLBW) and extremely low birthweight (ELBW) infants during the COVID-19 lockdown in Ireland: a ‘natural experiment’ allowing analysis of data from the prior two decades. BMJ Glob Health 2020;
• 8 Been JV, Burgos Ochoa L, Bertens LCM. et al. Impact of COVID-19 mitigation measures on the incidence of preterm birth: a national quasi-experimental study. Lancet Public Health 2020; 5: e604-e611
• 9 Askitas N, Tatsiramos K, Verheyden B. Estimating worldwide effects of non-pharmaceutical interventions on COVID-19 incidence and population mobility patterns using a multiple-event study. Sci Rep 2021; 11: 1972
• 10 Robert Koch-Institut. COVID-19 Datenhub. 2021 Accessed April 01, 2021 at: https://npgeo-corona-npgeo-de.hub.arcgis.com/datasets/ef4b445a53c1406892257fe63129a8ea_0/explore?location=51.164254%2C8.127781%2C6.73&showTable=true
• 11 Schlosser F, Maier BF, Jack O. et al. COVID-19 lockdown induces disease-mitigating structural changes in mobility networks. Proc Natl Acad Sci U S A 2020; 117: 32883-32890
• 12 Wood SN. Generalized Additive Models – An Introduction with R. 1st ed.. ed. Chapman and Hall/CRC; 2006
• 13 Wood SN, Goude Y, Shaw S. Generalized additive models for large data sets. Journal of the Royal Statistical Society: Series C (Applied Statistics) 2015; 64: 139-155
• 14 Brockmann D. Covid-19 Mobility Project. 2021 Accessed May 05, 2021 at: https://www.covid-19-mobility.org/
• 15 Dong M, Qian R, Wang J. et al. Associations of COVID-19 lockdown with gestational length and preterm birth in China. BMC Pregnancy Childbirth 2021; 21: 795
• 16 Pasternak B, Neovius M, Soderling J. et al. Preterm Birth and Stillbirth During the COVID-19 Pandemic in Sweden: A Nationwide Cohort Study. Ann Intern Med 2021; 174: 873-875
• 17 Arnaez J, Ochoa-Sangrador C, Caserio S. et al. Lack of changes in preterm delivery and stillbirths during COVID-19 lockdown in a European region. Eur J Pediatr 2021; 180: 1997-2002
• 18 Matheson A, McGannon CJ, Malhotra A. et al. Prematurity Rates During the Coronavirus Disease 2019 (COVID-19) Pandemic Lockdown in Melbourne, Australia. Obstet Gynecol 2021; 137: 405-407
• 19 Berghella V, Boelig R, Roman A. et al. Decreased incidence of preterm birth during coronavirus disease 2019 pandemic. Am J Obstet Gynecol MFM 2020; 2: 100258
• 20 Meyer R, Bart Y, Tsur A. et al. A marked decrease in preterm deliveries during the coronavirus disease 2019 pandemic. Am J Obstet Gynecol 2021; 224: 234-237
• 21 Chmielewska B, Barratt I, Townsend R. et al. Effects of the COVID-19 pandemic on maternal and perinatal outcomes: a systematic review and meta-analysis. Lancet Glob Health 2021;
• 22 Oakley LL, Ortqvist AK, Kinge J. et al. Preterm birth after the introduction of COVID-19 mitigation measures in Norway, Sweden, and Denmark: a registry-based difference-in-differences study. Am J Obstet Gynecol 2021;
• 23 an der Heiden M, Hamouda O. Schätzung der aktuellen Entwicklung der SARS-CoV-2-Epidemie in Deutschland – Nowcasting. Epidemiologisches Bulletin 2020; 2020: 10-15
• 24 Klumper J, Kazemier BM, Been JV. et al. Association between COVID-19 lockdown measures and the incidence of iatrogenic versus spontaneous very preterm births in the Netherlands: a retrospective study. BMC Pregnancy Childbirth 2021; 21: 767
• 25 Gomez GB, Mahé C, Chaves SS. Uncertain effects of the pandemic on respiratory viruses. Science 2021; 372: 1043-1044
• 26 Huang QS, Wood T, Jelley L. et al. Impact of the COVID-19 nonpharmaceutical interventions on influenza and other respiratory viral infections in New Zealand. Nat Commun 2021; 12: 1001
• 27 WHO. Review of global influenza circulation, late 2019 to 2020, and the impact of the COVID-19 pandemic on influenza circulation. 2021 Accessed November 02, 2021 at: https://www.who.int/publications/i/item/who-wer-9625-241-264
• 28 Buchholz U, Buda S, Prahm K. Abrupter Rückgang der Raten an Atemwegserkrankungen in der deutschen Bevölkerung. Epidemiologisches Bulletin 2020; 2020: 7-9
• 29 Ortiz A, Guerreiro C. Air Quality in Europe – 2020 report. 2020 Accessed December 01, 2021 at: https://www.actu-environnement.com/media/pdf/36559.pdf
• 30 Bekkar B, Pacheco S, Basu R. et al. Association of Air Pollution and Heat Exposure With Preterm Birth, Low Birth Weight, and Stillbirth in the US: A Systematic Review. JAMA Netw Open 2020; 3: e208243
• 31 Lebel C, MacKinnon A, Bagshawe M. et al. Elevated depression and anxiety symptoms among pregnant individuals during the COVID-19 pandemic. J Affect Disord 2020; 277: 5-13
• 32 Bussières E-L, Tarabulsy GM, Pearson J. et al. Maternal prenatal stress and infant birth weight and gestational age: A meta-analysis of prospective studies. Developmental Review 2015; 36: 179-199