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Jennifer Bogle/Stocksy United

Pregnancy comes with many physical and emotional changes that sometimes catch you by surprise. You’re likely to be super-aware of what’s happening to your body and may find yourself noticing — and googling! — every symptom, including any new rash or fever.

And the truth is, you should pay attention to rashes and fevers — both are symptoms you need to tell your doctor about during pregnancy. But here’s why you probably don’t have roseola, and what it means if you do.

Roseola is a mild viral infection that causes a sudden high fever and is usually followed by a rash. Roseola is also called:

  • three-day fever because the high fever lasts between 3 and 7 days
  • three-day rash because the harmless rash lasts 1 to 3 days and is made up of pink or red spots that pale when you press them (not everyone develops a rash, but those who do will spot when the fever ends)
  • roseola infantum because it’s most common in children between 6 and 12 months, with 90 percent of cases occurring in children under 2 years old

Roseola is caused by one of two viruses in the herpes family: human herpesvirus 6 (HHV 6) and, less often, by human herpesvirus 7 (HHV 7).

Although the virus isn’t highly infectious, it spreads easily through small droplets of fluid when the infected person sneezes, coughs, or leaves traces of saliva on surfaces.

Almost all of us are exposed to roseola during our childhood and develop the antibodies to fight off a second infection. So the chances of getting roseola when you’re pregnant are very low.

In fact, one very dated (1992) case study of a pregnant woman with roseola couldn’t even find previous reports of roseola in pregnancy, and newer studies about the infection haven’t addressed numbers in pregnancy at all.

More recent (but still not necessarily current) research gives us a better understanding of what happens in the rare cases when pregnant people get roseola.

A 2001 study showed significantly higher levels of both HHV 6 and HHV 7 antibodies in infants whose mothers had antibodies to both viruses. This suggests that the antibodies are actively carried over to the fetus via the placenta.

A different 1999 study showed that the transfer of HHV 6 to the fetus seems common during pregnancy and may occur in approximately 1 percent of pregnancies.

When it comes to how roseola affects your baby, opinion among researchers is divided. One study suggests that while we don’t know for sure, roseola may be associated with developmental disability. An additional study supports this and suggests that HHV 6 may affect a baby’s neurological development.

There is a lack of recent research within the past 10 to 15 years about pregnancy and roseola, in and of itself supporting the idea that this just isn’t common.

Since most adults get roseola as children, it’s unlikely that they’ll get it a second time. If they do, the good news is that symptoms are most likely to be light. Symptoms include:

  • fever
  • loss of appetite
  • sore throat
  • runny nose
  • swollen lymph nodes
  • roseola rash

In rare cases, people with an immune system that has been lowered by a transplant or cancer may contract a new case of roseola or have a repeat outbreak.

Is it contagious?

If you get roseola as an adult, you have the same chances of passing it on in the droplets from your respiratory system and your saliva as a child would.

However, since you have more awareness, you’ll more easily be able to stop those infectious droplets from spreading by taking all the standard precautions — staying home, covering your cough, distancing yourself from others, and wearing a mask.

The first step is to discuss your concerns with your doctor. Keep in mind that it’s most likely that you were already exposed to roseola when you were younger. However, if you’re among the few adults who wasn’t, there may be a slight risk to your baby.

It’s very unlikely that you’ll get roseola during pregnancy — or at any other time during adulthood. But it is possible. Perhaps more importantly, there are other reasons for rash during pregnancy — some of them serious — so you should always let your doctor know if you develop this symptom.