Measles and pregnancy: Navigating the risks during an outbreak
March 19, 2025
You have likely seen the news coverage of the measles outbreak in West Texas, New Mexico, and Oklahoma that started in late January 2025. Case numbers continue to increase, and if you are pregnant or considering pregnancy like many of my patients, you probably have questions:
Why is this happening now? Am I at risk? Is my baby? Should I be vaccinated? If I’m not vaccinated, how can I minimize the risk?
Let’s go through the answers together as we review facts, figures, and history about measles in America.
Jump to:
Symptoms | How it spreads | Vaccine guidelines
Why are measles cases on the rise?
Measles is one of the most contagious viruses in the world. It is easily spread via respiratory droplets – breathing, talking, sneezing, or coughing. In 2000, measles was considered officially eliminated from the United States thanks to a robust childhood vaccine program. But in recent years, vaccination rates have declined.
More than 90% of a community must be vaccinated to reach “herd immunity” and slow or stop the spread of measles. Certain areas in Texas – including some school districts in Dallas-Fort Worth – have fallen below that 90% threshold. Once you add in the ease of travel in the U.S. and abroad, as well as students attending school while they are contagious but before they show signs of infection, there is the potential for rapid spread.
If I’m pregnant, what is the measles risk for me and my baby?
In addition to the usual symptoms of measles – cough, runny nose, red and watery eyes (conjunctivitis), and tiny white spots (Koplik's spots) in the mouth, followed by a red, blotchy rash – measles in pregnant women who are not vaccinated can increase the risk of miscarriage, premature labor, low birth weight, and possibly maternal death from secondary infectious complications like pneumonia.
Measles has not been shown to cause birth defects in the developing fetus. But research has found that maternal infection toward the end of pregnancy can be associated with severe respiratory complications for your baby after birth. The measles infection may also be transmitted to your newborn.
Can I get vaccinated against measles when I’m pregnant?
During pregnancy, women are advised against getting the measles, mumps, and rubella (MMR) vaccine. That’s because it is a “live” vaccine, which means it contains weakened, or attenuated, versions of the viruses to provoke the body’s immune response. The weakened viruses could potentially cross the placenta and infect the fetus, which is why it’s recommended that women get vaccinated before getting pregnant or wait until after they give birth. The vaccine is safe for breastfeeding women and does not affect their babies.
The MMR vaccine is part of the recommended pediatric vaccine regimen. About 91% of children age 19-35 months in the U.S. have been vaccinated, according to the Centers for Disease Control and Prevention (CDC). So, check your vaccine records to see if you had an MMR vaccine as a child. The first dose is usually given at 12 months with a second dose coming at 4-6 years old.
If unvaccinated, how can I minimize risks for me and my baby?
For those who have not been vaccinated, consider wearing an N95 mask when out in public to reduce the likelihood of infection. Also, wash your hands regularly for at least 20 seconds, and avoid touching your face. Remind others in your home or who come in close contact with your baby to do the same.
If I get vaccinated now, how soon will I have protection?
For those who are not pregnant or too young (less than 6 months) or have another contraindication such as impaired immune system function, the MMR vaccine is readily available. It is a simple, low-risk way to protect yourself and, indirectly, those who cannot receive the vaccine. Full protection starts within two weeks of receiving the vaccine. Some degree of protection starts after only a few days.
The first dose of the measles vaccine is 93% effective in preventing infection. After the recommended second dose, it is 97% effective in preventing infection if exposed. Even if infection were to occur after vaccination, due to presence of antibodies, severe infectious complications are unlikely.
What if I’ve been exposed to measles?
If you are pregnant and suspect exposure to measles, call your doctor right away. If you are unsure about your vaccination status, we can offer a test to assess your immunity. And if you are within six days of exposure, you might be able to receive IV immunoglobulin treatment to reduce the likelihood of infection.
If you are not pregnant or you are concerned about an exposure in a friend or family member, know that moving quickly can still allow for MMR vaccination within 72 hours of the exposure, which prevents the illness in most people.
Measles 101: History, symptoms, and more
The first written description of measles dates back to the ninth century by a Persian physician. There are reports of rapid spread through Europe and Asia in the Middle Ages. By the 16th century, with increased travel and migration, it was considered a global risk. In the 18th and 19th centuries measles was a major cause of death in children because medical interventions were limited.
For those born prior to the 1960s, it was assumed they had had measles by the time they were 15. Despite advancements in medical care available in the mid- to late-1950s, the CDC reports that about 3-4 million people in the U.S. were infected each year, about 48,000 people were hospitalized, and 1,000 developed encephalitis, or swelling of the brain. During that time, an estimated 400-500 people died every year from measles. The measles vaccine became available to the public in 1963.
Measles symptoms: Cold, fever, Koplik' spots, and rash
- The first 3-5 days of measles symptoms can present much like a cold or the flu with a cough, runny nose, fatigue, fever, and red and watery eyes.
- About 70% of people will have Koplik’s spots (small whitish spots in the mouth), which will precede the signature red blotches and rash by 1-2 days.
- The characteristic measles rash often starts at the hairline and progresses down the body, including the palms of the hands and soles of the feet, over 3-4 days.
- Appearance can vary based on skin tone, looking more pinkish or red in those with lighter skin while people with darker underlying skin may have a more subtle brown appearance or less color change from the rash.
It may start out as small spots, with some slightly raised, and then they may join together for irregularly shaped splotches. It is typically not itchy. - Acute infection can make the patient highly susceptible to secondary infectious complications, including pneumonia, ear infection, croup, and diarrhea. These occur in about 30% of measles cases.
- Neurological complications are uncommon, but acute disseminated encephalomyelitis – an autoimmune disorder that attacks nerve fibers in the brain and spinal cord – occurs in about 1 in 1,000 measles cases, often within two weeks of infection. Symptoms include fever, fatigue, headache, nausea, vomiting, seizures, coma, and potentially death.
- Subacute sclerosing panencephalitis (SSPE) is a persistent infection of the brain and typically occurs several years post-infection in those who were infected at a young age. This fatal complication of measles has an estimated frequency of 6.5-11 people per 100,000 cases.
How an outbreak happens
Measles is highly contagious and spreads via respiratory droplets.
- Infected people are contagious four days prior to having a rash through four days after the rash appears.
- The time between a person being exposed to the measles virus and having a fever is about 7-10 days. A rash typically appears 10-14 days after exposure (a range of 7-21 days has been noted). This means that someone may think they just have a cold for about a week and can be infecting others before the characteristic rash appears.
- The measles virus can remain in the air and on surfaces for two hours after an infectious person leaves the area.
- It takes only a small amount of the virus for the disease to spread. Measles is more infectious than other easily transmitted illnesses such as influenza, COVID-19, and tuberculosis.
- If a group of 10 people who are not immune to measles are exposed, nine of them will become infected. They can each infect 90% of the non-immune people with whom they share air space. Then those people infect more people, and on and on.
- On the other hand, if more than 90% of a population is immune, the spread stops quickly because the virus has minimal opportunity to infect others.
Vaccination guidelines for children and adults
- A first dose is given at 12 months of age, and the second is usually given between 4-6 years old.
- During an outbreak, the CDC recommends a first dose as early as 6-11 months of age, followed by the routine dose at 12-15 months old, and a third dose at 4-6 years old.
- If someone is older and has not previously been vaccinated, the first dose can be administered at any time with a second dose coming at least 28 days later.
- For most adults a single dose is sufficient. Taking active precautions against becoming pregnant are recommended for four months after receiving the MMR vaccination.
A final word
During a measles outbreak, the potential for misinformation being shared increases. So let’s address that head on. In 1998, a very small and methodologically flawed study suggested an association between the MMR vaccine and autism. The study was later retracted due to scientific misconduct by the author. Since then, multiple, large-scale, properly conducted studies across the world have found no link between the MMR vaccine and autism.
At UT Southwestern, we are dedicated to improving and safeguarding the health and well-being of pregnant women and their children. We endorse childhood vaccinations on the schedule recommended by the American Academy of Pediatrics for the best protection against measles as well as mumps and rubella.
If you have questions or would like to consult with a physician at UT Southwestern, please call 214-645-8300 or request an appointment.
