COVID-19 restrictions linked to reduced preterm birth rates

COVID-19 restrictions linked to reduced preterm birth rates | Image Credit: © Halfpoint - © Halfpoint - stock.adobe.com.

The prevalence of preterm birth is reduced by efforts to mitigate exposure to COVID-19, according to a recent study published in JAMA Network Open.¹

Access to health care measures and personal attitudes toward utilization of medical services were significantly altered by the COVID-19 pandemic. Trials have been conducted to evaluate the association between the COVID-19 pandemic and preterm birth rates but have found varying results.

Efforts to prevent COVID-19 infections have been proven not to increase the risk of preterm birth.² A systematic review reported no significant association between COVID-19 vaccination during pregnancy and preterm birth risk, with a pooled odds ratio (OR) of 1.03.

While preterm birth rates were reduced following the 2020 lockdown in the United States, this decline was attributed to lower rates of cesarean delivery and induced delivery.¹ Additionally, most analyses did not highlight associations between the COVID-19 pandemic and baseline maternal characteristics.

Investigators conducted a cohort study to evaluate the association between the COVID-19 pandemic and causes of preterm birth. Data was obtained from the quality assurance registry of Hesse, which includes all stillbirths of at least 500 g and all live births with at least 22 weeks’ gestation.

Evaluations focused on very preterm (VPT) infants born at under 32 weeks’ gestation, with results categorized based on maternal baseline characteristics and causes of VPT birth. Additional assessments were performed for infants born from 32 to 36 weeks’ gestation.

In Hesse, COVID-19 restrictions were implemented on March 14, 2020. Phases included the first lockdown from March 14 to May 15, 2020, a period of less vigorous restrictions from May 16 to October 18, 2020, and a second lockdown from October 19 to December 31, 2020.

Outcomes were compared to a prepandemic period from 2017 to 2019. Preterm birth rates were reported as the primary outcome, with categories for preterm delivery including spontaneous onset with preterm labor, amniotic infection, and premature rupture of membranes.

Maternal baseline characteristics included maternal age, preterm birth history, maternal or family serious death history, previous cesarean delivery or uterine surgery, prior pregnancy complications, and singleton or multiple pregnancy. Pregnancy risks included diabetes, obesity, severe psychological burden, preexisting hypertension, and placenta previa.

There were 184,827 births included in the final analysis, 719 of which were stillbirths and 184,108 were live births. The rate of overall live births was reduced by 4.9% in 2020 vs the prepandemic period. Additionally, the rate of VPT births was 1.29% in 2020 vs 1.47% during the prepandemic period, and the OR for preterm birth was 0.87.

When comparing the rates of total birth from a period between 2017 and 2019 to a period between 2017 and 2020, an accelerated decrease of VPT births was observed in the latter. Additionally, the most significant reduction in VPT birth was observed during the third period, with an OR of 0.69.

Stillbirth rates did not differ between prepandemic and pandemic periods, nor did prenatal care characteristics. The risk of VTP birth was reduced among women with a history of serious maternal disease, with an OR of 0.64, but changes were not observed among other factors.

Most causes of preterm birth also remained unchanged between the prepandemic and pandemic periods. However, a reduction in the frequency of births for intrauterine infection was observed among VPT infants during the pandemic. Additionally, the odds of births for pathologic cardiotocography were reduced, with an OR of 0.66.

These results indicated an association between COVID-19 mitigation efforts and reduced preterm birth rates. Investigators recommended additional research about primary preventive measure and different causes of preterm delivery.

References

1. Staude B, Misselwitz B, Louwen F, et al. Characteristics and Rates of Preterm Births During the COVID-19 Pandemic in Germany. JAMA Netw Open. 2024;7(9):e2432438. doi:10.1001/jamanetworkopen.2024.32438
2. Krewson C. COVID-19 vaccination during pregnancy not linked to preterm birth. Contemporary OB/GYN. January 31, 2024. Accessed September 19, 2024. https://www.contemporaryobgyn.net/view/covid-19-vaccination-during-pregnancy-not-linked-to-preterm-birth