Although pregnant women have many of the same initial virus symptoms as other people, they face greater odds of complications, Parodi said.
"During pregnancy, the immune system has different components. A pregnant woman's immune system shifts away from the ability to fight off viruses and shifts more toward fighting bacteria," Parodi said. "It puts them at higher risk of viral influenza."
The growth of the baby compresses a woman's lungs, so her breathing capacity is reduced. "With less lung capacity, you're more likely to get sick," he said. "And if you get an infection, it's harder to clear."
Flu seems to also increase the risk of delivery complications, such as spontaneous abortion and preterm birth, especially among women with pneumonia.
Additionally, it poses problems for the baby, if the woman has high fever. Studies show that maternal fever during the first trimester doubles the risk of neural tube defects and other birth defects. Maternal fever during labor is a risk factor for seizures, encephalopathy, cerebral palsy and infant death. Doctors recommend treatment with acetaminophen to reduce a pregnant woman's fever.
In England, initial hysteria over infection caused the nation's Department of Health to advise women to consider delaying conception until the pandemic passed. The Royal College of Midwives and the Royal College of Obstetricians and Gynecologists also advised pregnant women to avoid rush hour, stay indoors and restrict the movement of other children so the virus didn't get brought home. But both groups have since softened their stance.
Pregnant women should feel free to work, play and do other normal activities, Parodi said.
"Pregnant women should avoid people who are coughing or actively ill," he said. "And if we're ill, we should protect them, by not going to work. It's a way we can all help."
An elevated number of influenza-associated deaths among pregnant women were reported during the pandemics of 1918-1919 and 1957-1958. In a study of 1,350 women who had flu during the 1918 pandemic, about half the women got pneumonia and about half of the women with pneumonia died — a case-fatality rate of 27 percent. During the 1957 flu pandemic, pregnant women accounted for half of the flu deaths in a study of Minnesota women of reproductive age.
I wonder if the Vatican (or even Lutherans) would consider this current pandemic a "serious" and "grave" reason to avoid conception.