The association between seasonal influenza-like illness cases and foetal death: a time series analysis

Influenza Activity and Preterm Birth in the Atlanta Metropolitan Area: A Time-Series Analysis from 2010 to 2017

BACKGROUND

Annual influenza epidemics lead to a substantial public health burden, and pregnant people are vulnerable to severe outcomes. Influenza during pregnancy is hypothesized to increase the risk of adverse birth outcomes, but population-based epidemiologic evidence remains limited and inconsistent.

METHODS

We conducted a time-series analysis to estimate short-term associations between community-level seasonal influenza activity and daily counts of preterm births in Atlanta, United States from October 17, 2010 to July 10, 2017. We defined weekly influenza exposures four ways: (1) percent test-positive from virologic surveillance, (2) percent of patients with symptoms of influenza-like illness (ILI) in outpatient settings, (3) a composite measure of percent test-positive and ILI, and (4) influenza hospitalization rates. We used Poisson log-linear models to estimate associations, adjusting for time-varying confounders and ongoing at-risk pregnancies. We further examined associations by influenza type and exposure lags and effect modification by maternal characteristics.

RESULTS

We studied a total of 316,253 births. We found consistent positive associations between influenza activity and preterm birth across different exposure measures and exposure lags. An interquartile range increase in a composite measure of ILI activity and percent test-positive was associated with a 1.014 (95% confidence interval: 1.001-1.027) increase in preterm birth during the same week. In stratified analyses, associations were more pronounced among married, non-Black, and Hispanic pregnant people.

CONCLUSION

Periods of high influenza activity were associated with an increased risk of preterm birth.

Prenatal screening diagnosis and management in the era of coronavirus: the Sardinian experience

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a new coronavirus, was first identified in December 2019 in Wuhan, China and spread rapidly, affecting many other countries. The disease is now referred to as coronavirus disease 2019 (COVID-19).The Italian government declared a state of emergency on 31st January 2020 and on 11th March World Health Organization (WHO) officially declared the COVID-19 outbreak a global pandemic. Although the COVID-19 incidence remained considerably lower in Sardinia than in the North Italy regions, which were the most affected, the field of prenatal screening and diagnosis was modified because of the emerging pandemic. Data on COVID-19 during pregnancy are so far limited. Since the beginning of the emergency, our Ob/Gyn Department at Microcitemico Hospital, Cagliari offered to pregnant patients all procedures considered essential by the Italian Ministry of Health. To evaluate the influence of the COVID-19 pandemic on the activities of our center, we compared the number of procedures performed from 10th March to 18th May 2020 with those of 2019. Despite the continuous local birth rate decline, during the 10-week pandemic period, we registered a 20% increment of 1st trimester combined screening and a slight rise of the number of invasive prenatal procedures with a further increase in chorionic villi sampling compared to amniocentesis. Noninvasive prenatal testing remained unvariated. The request for multifetal pregnancy reduction as a part of the growing tendency of voluntary termination of pregnancy in Sardinia increased. The COVID-19 pandemic provides many scientific opportunities for clinical research and study of psychological and ethical issues in pregnant women.

Considerations for Obstetric Care during the COVID-19 Pandemic

The novel coronavirus disease 2019 (COVID-19) is a growing pandemic that is impacting daily life across the globe. Though disease is often mild, in high-risk populations, severe disease often leads to intubation, intensive care admission (ICU) admission, and in many cases death. The implications for pregnancy remain largely unknown. Early data suggest that COVID-19 may not pose increased risk in the pregnant population. Vertical transmission has not been confirmed. Because no treatment, no vaccine and no herd immunity exist, social distancing is the best mechanism available to protect patients and health care workers from infection. This review will discuss what is known about the virus as it relates to pregnancy and then consider management considerations based on these data. KEY POINTS: · COVID-19 severity in pregnancy is unclear.. · Social distancing is the best protective mechanism.. · No clear evidence of vertical transmission exists.. · Mother/baby separation avoids transmission..

Seasonal and pandemic influenza during pregnancy and risk of fetal death: A Norwegian registry-based cohort study

Previous studies of fetal death with maternal influenza have been inconsistent. We explored the effect of maternal influenza-like illness (ILI) in pregnancy on the risk of fetal death, distinguishing between diagnoses during regular influenza seasons and the 2009/2010 pandemic and between trimesters of ILI. We used birth records from the Medical Birth Registry of Norway to identify fetal deaths after the first trimester in singleton pregnancies (2006-2013). The Norwegian Directorate of Health provided dates of clinical influenza diagnoses by primary-health-care providers, whereas dates of laboratory-confirmed influenza A (H1N1) diagnoses were provided by the Norwegian Surveillance System for Communicable Diseases. We obtained dates and types of influenza vaccinations from the Norwegian Immunisation Registry. Cox proportional-hazards regression models were fitted to estimate hazard ratios (HRs) of fetal death, with associated 95% confidence intervals (CIs), comparing women with and without an ILI diagnosis in pregnancy. There were 2510 fetal deaths among 417,406 eligible pregnancies. ILI during regular seasons was not associated with increased risk of fetal death: adjusted HR = 0.90 (95% CI 0.64-1.27). In contrast, ILI during the pandemic was associated with substantially increased risk of fetal death, with an adjusted HR of 1.75 (95% CI 1.21-2.54). The risk was highest following first-trimester ILI (adjusted HR = 2.28 [95% CI 1.45-3.59]). ILI during the pandemic-but not during regular seasons-was associated with increased risk of fetal death in the second and third trimester. The estimated effect was strongest with ILI in first trimester.