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Let’s Talk About Congenital Measles

By / / congenital measles, fetal measles, maternal measles, measles encephalitis, measles in pregnancy, MMR, neonatal measles, perinatal measles

Tragically, congenital measles is a thing.

Pregnant women have been getting caught up in recent measles outbreaks, and so have their babies.
Pregnant women have been getting caught up in recent measles outbreaks, and so have their babies. Also know that IVIG post-exposure prophylaxis to prevent you from actually getting measles is available if you are pregnant, not immune, and have been exposed to someone with measles. IVIG can also be given to babies.

A thing that is coming back, as we are seeing more cases of measles.

Let’s Talk About Congenital Measles

Classically, we think of congenital measles as:

  • clinical illness compatible with measles with symptom onset in the first 10 days of life, or
  • laboratory detection of measles virus RNA by PCR when the the specimen was collected and/or symptom onset was within the first 10 days of life in a neonate whose mother/birthing parent was a confirmed or probable measles case and/or in a neonate with no other suspected source of exposure to measles after birth.

Wait, that sounds like the baby who died in Pennsylvania, doesn’t it?

Now, can you guess why they use “the first 10 days of life” in the case definition, when “congenital” usually means that something was present at birth?

That’s the minimum incubation period for measles!

So a baby could have been born with measles, but might not show symptoms until they are 10 days old.

Well actually, since the incubation period for measles is 10 to 21 days, they could have been born with measles and not have symptoms until they were 21 days old! But that’s where it gets confusing. After 10 days, you couldn’t be sure if they were born with measles or if they had been exposed after they were born…

What else?

Having congenital measles means that the baby was exposed to measles in utero, by their mother, before they were born.

It is related to:

  • maternal measles in pregnancy – can lead to premature delivery, spontaneous abortion, or low birth weight, even when the fetus isn’t infected with measles
  • fetal measles infections – since the measles virus can cross the placenta, it can infect a fetus earlier in the pregnancy if that is when the mother is sick with measles
  • neonatal measles infections – measles in a newborn in the first 28 days of their life, which can be congenital or acquired after they were born
  • perinatal measles infections – measles in a newborn acquired around the time of birth

And, of course, they are all related by the simple fact that if a baby gets measles, then the mother was likely not immune. She either was either never vaccinated or never had a natural measles infection. After all, maternal measles antibodies should be able to protect a newborn baby from measles.

Recent Cases of Congenital Measles

Lastly, would it surprise you to know that there have been more than a few cases of congenital measles associated with the outbreaks we have been having in recent years?

In Canada, where they do a better job of tracking congenital measles cases, there were at least 19 cases last year, including one baby who died.

This includes reports of:

  • a 34-week premature baby with measles in New York (2019)
  • a 25-week premature baby with measles in New York (2019)
  • at least two cases of congenital measles in Texas (2025) among four pregnant women with measles, and one baby who developed acute measles meningoencephalitis!
  • at least one case of congenital measles in Utah (2026), in a baby who reportedly had a life-threatening case

Of course, this is almost certainly an undercount, as congenital measles isn’t a separately nationally notifiable condition, although it certainly should be!

This 15 day old baby had a “severe disease course” after getting measles from his mother and spent 11 days in the PICU.
This 15 day old baby had a “severe disease course” after getting measles from his mother and spent 11 days in the PICU. Photo CC by 4.0.

One more thing!

During the large measles outbreaks from 1989 to 1991, among 55,622 cases of measles and 123 deaths, there were at least:

  • 58 pregnant women with measles
  • five pregnancies ended in spontaneous abortion
  • 13 pregnancies in preterm delivery
  • one maternal death

And yes, with rising case counts, this may be where we are headed over the next few years.

Bottom line – get vaccinated with two doses of the MMR vaccine before you think about getting pregnant so that your baby doesn’t get measles!

More on Congenital Measles

Last Updated on August 29, 2026

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