Stillbirth Risk during the 1918 Influenza Pandemic in Arizona, USA.

Area of Science:

• Epidemiology
• Public Health
• Obstetrics

Background:

• The 1918 influenza pandemic was a global health crisis, impacting a third of the world's population.
• The relationship between this pandemic and stillbirth risk requires further in-depth investigation.

Purpose of the Study:

• To assess the impact of the 1918 influenza pandemic on stillbirth risk in Arizona, USA.
• To analyze demographic factors influencing stillbirth risk during the pandemic.

Main Methods:

• Retrospective study utilizing 21,334 birth records from Maricopa County, Arizona (1915-1925).
• Logistic regression analysis to determine the pandemic's effect on stillbirth risk.
• Examination of stillbirth rates in relation to maternal age and pandemic timing.

Main Results:

• No statistically significant overall increase in stillbirth risk during the pandemic.
• A notable peak in stillbirth risk (42/1000 births) occurred in July 1919, 9 months after peak pandemic mortality.
• Mothers aged 35 and older faced a 1.42 times higher risk of stillbirth.
• Optimal maternal age for lowest stillbirth risk was approximately 26 years.
• Stillbirth risk peaks were observed 9-10 months post-peak pandemic mortality.

Conclusions:

• The 1918 influenza pandemic's impact on stillbirth risk was complex, with delayed peaks observed.
• Maternal age is a significant factor in stillbirth risk, especially during and after major infectious disease outbreaks.
• Findings contribute to understanding the long-term reproductive health consequences of pandemics.