Temperature Rise and other Normal Pregnancy Changes Confused with COVID-19

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Your body temperature is up slightly, it’s a little difficult to breathe, and your sense of smell is not right. You google these symptoms and are horrified to find that the search has brought up several articles about COVID-19. Is this what you are likely to have and should you go find a place to get tested? The answer is that it depends on a variety of factors —the severity of your symptoms first of all, as well as the context in which they are occurring, including whether you have other symptoms, such as a cough, and one other factor: might you be pregnant?

As you know, these blog posts are not to be taken as medical advice, but they are for education. Anybody with any breathing difficulty needs to see some kind of doctor, but it’s quite possible that you need an obstetrician, rather than an infectious disease specialist. That’s because some difficult or labored breathing —what doctors call dyspnea— is actually quite common in normal pregnancy. But dyspnea is also one of the three most common presenting symptoms of COVID-19, the other two being fever and cough. Additionally, though not as common as the aforementioned symptoms, some people who develop COVID-19 also suffer a more unusual symptom in which they lose their sense of smell. Consequently, if you google dyspnea (or breathing difficulty), along with smell and anything related to temperature, or if you ask Siri or Alexa about any such a combination of experiences, COVID-19 articles are what will come up.

Now, especially in the COVID-19 era, if you are suffering a fever and/or any respiratory symptoms, you certainly should notify your primary care physician (PCP). You ought not to be running to the emergency room, but you should contact your doctor’s office and set up a telemedicine visit via online video conferencing, such as Zoom conferencing, Facetime, Skype, or an audio phone call. That said, let’s unpack some of the symptoms that we mentioned above and let’s do it in a pregnancy context.

In pregnancy, shortness of breath —dyspnea— can be part of a disease process exacerbated by pregnancy, such as anemia, or a heart condition. Very commonly, a woman of child bearing age can be hovering on the border of anemia with no symptoms and pregnancy can push her into the symptomatic realm. Similarly, a woman may have a heart valve abnormality, such as mitral stenosis (narrowing of the opening in the valve through which blood moves from the left atrium to the left ventricle) that is mild normally, but worsens due to an increase in the volume of blood that occurs during pregnancy. Dyspnea during pregnancy also can be a telltale sign of a life threatening condition called pulmonary embolism. However, dyspnea also can develop simply due to pregnancy changing the shape of the lungs, knocking the circulation of blood through different parts of lungs out of synch with amounts of blood moving through those parts of the lungs (called ventilation perfusion mismatch). Finally, and very dramatically, the pregnancy hormone progesterone actually changes the settings on the respiratory drive in your nervous system, making you want to breathe more. This helps compensate for an increased need for oxygen in order to supply oxygen to the fetus, but the drive to breathe more has the effect of making you feel as if you’re not getting enough air. In other words, it makes you dyspneic.

As for temperature increase, it’s actually very common and normal for body temperature to rise slightly from the normal 37° C (98.6 F, for Americans), such as to 37.5° or even 37.8°. But, to be a COVID-19 symptom, elevated temperature really has to reach the realm of fever, which generally is defined as body temperature at least 38.0° (100.4 F).

Due to fluid changes and changes in various hormones, it’s not uncommon for a woman’s sense of smell and taste to change over the course of pregnancy, but with COVID-19 there have been reports of many people losing the sense of smell as an early symptom. Known as anosmia, the loss of smell also affects one’s taste, since the latter is influenced greatly by the former.

Clinical context is very important. Whereas difficulty breathing is a serious symptom that requires medical evaluation, one important consideration in patients with dyspnea is whether and to what degree it is associated with deficiencies in the movement of oxygen and carbon dioxide between the air and blood. If the level of carbon dioxide in the blood and the acidity of the blood are normal, then your lungs are removing carbon dioxide adequately from the blood. If the hemoglobin in your red blood cells is saturated adequately with oxygen, this means that enough oxygen is getting into the blood through the lungs. Consequently, if you suffer from respiratory symptoms, such as dyspnea, and if you’re being evaluated for COVID-19, your doctor will have you obtain a pulse oximetry device to use at home. It’s just a small device that goes on your finger and it tells you how close to 100 percent your hemoglobin is. Oxygen saturation of 95 percent or higher is considered normal and usually people have a saturation from 97 to 100 percent. In the event that you test positive for SARS-CoV2 (the virus that causes COVID-19), or if you are suspected of possibly having COVID-19 or that you have been exposed to somebody with the virus, if you have no other major health problems, generally you would not be admitted to the hospital, unless your oxygen saturation drops to 92 percent or lower.  With a saturation from 92-95 percent, if you have a major health condition, or if you are advanced in pregnancy, your doctors may decide to hospitalize you.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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