Echoing patterns observed amid COVID-19, historical data from a Swiss maternal hospital reveal a significant rise in low birth weight (LBW) and stillbirth during and after the 1918 flu pandemic, according to a study published yesterday in PLOS One.

University of Zurich researchers evaluated changes in birth weight, gestational age, and stillbirth rates at the Bern Maternity Hospital every 5 years from 1880 to 1900 and every year from 1914 to 1922. A total of 1,530 and 6,924 births were recorded before and during/after the flu pandemic, respectively.

The team used linear regression models to estimate the effect of birth year on birth weight and logistic regression models to estimate the effect of birth year and exposure to flu on premature birth, stillbirth, and LBW.

"It is estimated that nongenetic maternal and environmental factors account for 60–70% of the variation in birth weight," the authors wrote. "In contrast to adult height, birth weight is a more direct measure of nutritional status at the time of measurement (as it mirrors the inherited, biological and environmental influences over nine months of gestation)."

Double the risk of stillbirth in pandemic

Average birth weight increased slightly between the two periods (range, 3,058 grams (6.7 pounds) in 1895 to 3,172 grams (7.0 pounds) in 1921, but stillbirth rates fell markedly, ranging from 3.3% to 6.4% in 1914 to 1922, and preterm birth rates dropped to 13% to 16% in 1914. Infant sex, number of previous pregnancies, gestational age, and maternal age were significantly tied to birth weight during both periods.

This urges us to better prepare for future pandemics to mitigate their effects on maternal and neonatal health.

Compared with 1914, the odds of LBW rose significantly in 1918 (odds ratio [OR], 1.49) and 1919 (OR, 1.55). Mothers exposed to flu during pregnancy were at double the risk for stillbirth (OR, 2.27). The data on flu infection during pregnancy were imprecise and thus didn't allow individual-level conclusions.

"Pandemics are increasingly reported to negatively influence pregnancy outcomes," the study authors wrote. "This urges us to better prepare for future pandemics to mitigate their effects on maternal and neonatal health."

The New York State Department of Health (NYSDOH) yesterday urged residents to take precautions following the Vibrio death of a patient from Suffolk County, as well as similar fatal cases reported recently from Connecticut.

In a statement, New York officials said the case is still under investigation to determine if the patient was exposed to water in New York or elsewhere. The NYSDOH urged health providers to consider Vibrio vulnificus when evaluating patients with severe wound infections or sepsis without or without wound infection. It also urged people with wounds to avoid swimming in warm sea water and people with weakened immune systems to avoid handling or eating raw seafood that could carry the bacteria.

In late July, the Connecticut State Department of Health warned residents about the risk of eating raw shellfish and exposure to salt or brackish water along Long Island Sound after reports of severe Vibrio cases. Since July 1, the state has received reports of three cases, one of them fatal. Patients were between 60 and 80 years old, and all were hospitalized.

Given our current heat wave, this may be a time to exercise particular caution in what you consume.

One patient had eaten raw oysters at a location in another state. The other two were exposed to salt or brackish water in Long Island Sound. Both had pre-existing open cuts or wounds or had sustained new wounds during their activities.

Manisha Juthani, MD, Connecticut's health commissioner, said in the hottest months of summer, bacteria are more likely to overgrow and contaminate raw shellfish. "Given our current heat wave, this may be a time to exercise particular caution in what you consume."

Connecticut recorded five cases in 2020, but none in 2021 or 2022. North Carolina reported three Vibrio deaths in July.