Nick Foles’ wife, Tori, reveals she had a miscarriage. What you need to know about pneumonia during pregnancy.

Respiratory infections can be especially serious in pregnant women, as Tori Foles’ heartbreaking experience shows.

The wife of former Eagles quarterback Nick Foles revealed on Instagram on Wednesday that she suffered a miscarriage after 15 weeks of pregnancy with their second child and spent several days in the hospital. That’s why her husband, now with the Jacksonville Jaguars, missed team activities this week.

“Early Sunday morning after a rough couple days fighting a ‘virus’ of some sort, I went into sudden labor and knew something was wrong,” she wrote.

She explained that she “had contracted an infection of pneumonia in the blood. ... We are finally home from the hospital and recovering physically from the infection with antibiotics as well as emotionally from this traumatic loss.”

We asked Adeeb Khalifeh, a maternal-fetal medicine specialist at Einstein Medical Center, what women should know about pneumonia during pregnancy.

Pneumonia is a lung infection that can make the air sacs fill with fluid or pus, triggering cough, shortness of breath, fever, and chills. Pneumonia can start with a cold or flu, and can be caused by germs including bacteria, viruses, or even fungi.

The reason pneumonia is of special concern in pregnancy involves the woman’s immune system, which is tamped down to protect the fetus, Khalifeh explained.

“Pregnancy in general is a state of immunosuppression, so she is more susceptible to infection than when she is not pregnant,” he said. “Because the immune system is not optimal, the complications are worse in pregnancy than in non-pregnancy.”

That’s why the U.S. Centers for Disease Control and Prevention recommends that all pregnant women get the flu vaccine. And if cold or flu symptoms appear, don’t try to tough it out; see a doctor.

“If pregnant patients have symptoms, address them earlier,” he said.

The CDC does not recommend that pregnant women get the pneumococcal vaccine, which helps protect against the most common cause of bacterial pneumonia. Although there is no evidence that it is harmful, the CDC says women who need the shot because of unusual risk factors should get it before becoming pregnant.

If pneumonia moves into the bloodstream, it can become a crisis, not only posing a risk of miscarriage but also endangering the woman’s life. “Any serious infection that can spread to the bloodstream can become life-threatening,” Khalifeh said.

He noted, however, that miscarriage in the first trimester — through the end of the 12th week — is common, happening in about 20 percent of pregnancies, usually because of chromosomal abnormalities.

Tori Foles, 28, has a 2-year-old daughter, Lily, with her husband, 30. Although they are mourning the loss of “our baby boy,” they are healing. In addition to feeling “sadness, confusion and anger,” she described “a firm belief that God has this fully in his hands and will use this for good."