Last updated May 16, 2025
This Practice Advisory was developed by the American College of Obstetricians and Gynecologists.
Background
The United States is currently experiencing a concerning rise in measles (Rubeola) cases, including outbreaks in several states 1 . An outbreak is defined as three or more cases. More cases are expected as these outbreaks continue to expand rapidly. These measles outbreaks have been linked to travelers bringing back cases of measles from other countries and have so far mostly affected unvaccinated children including those who were age eligible for vaccination 2 . This situation combined with low vaccination coverage among certain communities in the United States leads to pockets of vulnerable communities.
Measles is a highly contagious viral airborne disease. The best protection against measles is the measles, mumps, and rubella (MMR) vaccine which provides long-lasting protection. An estimated 92–95% of individuals in a community must be immune to prevent ongoing transmission. Measles can cause serious illness and infects approximately 9 out of every 10 susceptible individuals exposed in close-contact settings 3 . Certain individuals, including unvaccinated and pregnant individuals, infants and children aged less than 5 years, and severely immunocompromised people are at increased risk of severe illness and complications of measles 3 . The best way to document immunity is to verify patients’ vaccination records. Because obtaining these records can be challenging, clinicians should offer MMR vaccine. If commercial IgG antibody tests are used to assess immunity, be aware that these tests are not 100 percent sensitive and may fail to detect preexisting immunity 4 5 .
Summary of Key Recommendations and Points
- Assessing Immunity: Obstetrician–gynecologists should assess the measles immunity status of all patients. Presumptive evidence of immunity can be established in any of the following ways:
- Written documentation of having adequate doses of the MMR vaccine, which includes having at least one dose of the MMR vaccine or two doses for people in certain groups.
- Laboratory evidence of immunity with IgG antibody tests. Be aware that commercial IgG antibody tests are not 100 percent sensitive and may fail to detect preexisting immunity. If there is a measles outbreak, clinicians need not test for evidence of immunity. Rather, they should ensure that non-pregnant teenagers and adults previously vaccinated with one dose of MMR vaccine receive a second dose. Non-pregnant patients with no evidence of immunity should receive one dose of MMR vaccine immediately and follow with a second dose at least 28 days later.
- Laboratory confirmation of disease
- Birth before 1957
- Discussing Vaccination: Obstetrician–gynecologists should discuss vaccination with all nonpregnant patients without presumptive evidence of immunity. Nonpregnant patients should be offered at least one dose of the MMR vaccine. All MMR doses must be separated by at least 28 days. MMR vaccination should not be administered during pregnancy, and it is recommended to avoid pregnancy for 28 days after receipt of MMR. However, MMR can be given in the postpartum period even while breastfeeding, ideally before hospital discharge.
- Vaccination of Healthcare Personnel: Healthcare personnel have a higher risk of exposure to measles and should have presumptive evidence of immunity to measles. During an outbreak of measles, healthcare facilities should recommend two doses of MMR vaccine for unvaccinated healthcare personnel regardless of birth year who lack laboratory evidence of measles immunity or lack laboratory confirmation of disease. Exposed healthcare personnel without presumptive evidence of immunity should receive post-exposure prophylaxis via the MMR vaccine within 72 hours of exposure.
- Diagnosis and Clinical Characteristics: Measles is characterized by fever, malaise, cough, conjunctivitis, a pathognomonic enanthema (Koplik spots) on the buccal mucosa, followed by a maculopapular rash. The incubation period for measles, from exposure to fever, is usually about 7–10 days. The rash usually appears about 14 days after a person is exposed. Measles infection in pregnant individuals is associated with several adverse events including increased risk of hospitalization, pneumonia and death.
- Notifying Health Departments: Obstetrician-gynecologists should first notify their local and/or state public health departments of any suspected measles cases.
- Testing and Reporting: Obstetrician–gynecologists should collect either a nasopharyngeal swab or throat swab for reverse transcription–polymerase chain reaction, as well as a blood specimen for serology from all patients with clinical features compatible with measles. Clinicians should also immediately notify their local and/or state health department.
- Isolation: Obstetrician–gynecologists should advise nonpregnant and pregnant patients with suspected or confirmed measles to immediately isolate. Postpartum patients with suspected or confirmed measles should immediately isolate; however, allow for shared medical decision making with the family for location of the infant after birth if the postpartum patient is infectious. Depending on the location of the infant, breastfeeding or feeding expressed breastmilk is beneficial. There is no contraindication to breastfeeding if a mother has measles 6 .
- Treatment of Exposed Cases: For nonpregnant patients exposed to measles who cannot readily show that they have previously received two doses of the MMR vaccine, obstetrician–gynecologists should offer postexposure prophylaxis via the MMR vaccine within 72 hours of exposure. For pregnant patients exposed to measles who cannot readily show that they have evidence of immunity against measles, offer postexposure prophylaxis with IV immunoglobulin (IVIG). For postpartum patients exposed to measles who cannot readily show evidence of immunity against measles, offer postexposure prophylaxis via the MMR vaccine within 72 hours of exposure.
- Vitamin A: Vitamin A does not prevent measles and is not a substitute for vaccination, nor does vitamin A treat measles alone. Pregnant patients and patients who may become pregnant should not consume more than 10,000 IU of preformed vitamin A per day. Taking excess preformed vitamin A before and during early pregnancy triples the risk of birth defects 7 .
MMR Vaccination and Measles Immunity
Assessing Immunity in Routine Settings
Obstetrician–gynecologists should assess the measles immunity status of all their pregnant and nonpregnant patients. MMR vaccine is recommended for all children in the United States starting at age 12–15 months with a second dose at age four through age six. Although most individuals have immunity to measles because of prior MMR vaccination, given the risks associated with measles in pregnancy, possible infection or exposure to measles should be carefully and expediently investigated. Evidence of immunity or lack thereof determines the next steps if a patient is exposed or in the outbreak setting 3 . While finding immunization records for patients to verify immunity from measles can be challenging, it provides critical information including how many doses have been administered. If records are not available, clinicians may consider assessing immunity with IgG antibody serologies. However, commercial IgG antibody tests can fail to detect pre-existing immunity due to suboptimal sensitivity 4 5 ; therefore, a positive result confirms no additional MMR doses are needed. If results are negative, non-pregnant patients are eligible for vaccination and pregnant patients may be vaccinated in the postpartum period, given MMR is a live attenuated vaccine.
Assessing Immunity in Areas of Outbreaks
In areas of measles outbreaks or possible exposures to measles, serologic testing for measles immunoglobulin (IgG) is not necessary and clinicians should immediately offer vaccination with the MMR vaccine or treatment for exposed patients with postexposure prophylaxis with immunoglobulin within 72 hours of exposure in consultation with their local or state health department. Non-pregnant teenagers and adults previously vaccinated with one dose of MMR vaccine should receive a second dose. Non-pregnant patients with no evidence of immunity should receive one dose of MMR vaccine immediately and follow with a second dose at least 28 days later.
Evidence of Immunity
Presumptive evidence of immunity can be established in any of the following ways:
- Written documentation of having adequate doses of the MMR vaccine, which includes having at least one dose of the MMR vaccine or two doses in specific groups (See Considerations for Specific Groups below).
- Laboratory evidence of immunity with IgG antibody tests. Be aware that commercial IgG antibody tests are not 100 percent sensitive and may fail to detect preexisting immunity. If there is a measles outbreak, clinicians need not test for measles antibodies in non-pregnant patients without evidence of immunity and instead encourage the MMR vaccine.
- Laboratory confirmation of disease
- Birth before 1957
Considerations for Specific Groups
Two doses of MMR vaccine at least 28 days apart are recommended for people in specific groups who do not have other evidence of immunity against measles, including:
- College students
- International travelers
- Healthcare personnel
- Close contacts of immunocompromised people
- People with HIV infection
One or two doses of MMR vaccine are recommended for:
- Adults who got inactivated measles vaccine. The inactivated vaccine was given to ~5% of MMR vaccine recipients during 1963-1967. Those who were known to have received inactivated vaccine or were vaccinated with an unknown type of vaccine during 1963-1967, should be revaccinated.
- Groups at increased risk during measles outbreak. During measles outbreaks, health departments may provide additional recommendations to protect their communities. The at-risk population is defined by local and state health departments and depends on the epidemiology of the outbreak (e.g., only specific age groups are affected).
Discussing Vaccination
Routine Settings
Obstetrician–gynecologists should discuss vaccination with all nonpregnant patients without presumptive evidence of immunity. Nonpregnant patients without evidence of immunity should be offered at least one dose of the MMR vaccine. All MMR doses must be separated by at least 28 days. MMR vaccination should not be routinely administered during pregnancy, and it is recommended to avoid pregnancy for 28 days after receipt of MMR. However, MMR vaccination in the periconception period or in early pregnancy should not be considered an indication for termination of pregnancy 8 .
For pregnant individuals without evidence of immunity, MMR vaccine should be administered in the postpartum period even while breastfeeding, ideally before discharge from the hospital 8 . MMR vaccine is safe in breastfeeding individuals and has not been shown to have adverse effects in neonates 6 .
Outbreak Settings
In outbreak settings in which adults are recommended to have two doses of MMR vaccine, an adult in the preconception or postpartum phases with only one prior dose should be offered a second dose. When indicated by health departments, infants 6–11 months of age may receive an early MMR dose. Subsequent doses should follow CDC’s recommended childhood schedule:
- Another dose at 12 through 15 months of age
- A final dose at four through six years of age
If a clinic office does not stock the MMR vaccine, non-exposed patients can be referred to obtain the vaccine at pharmacies by providing a written prescription or referred to the local health department.
Vaccination of Healthcare Personnel
- Healthcare personnel have a higher risk of exposure to measles and should have presumptive evidence of immunity to measles 9 .
- During an outbreak of measles, healthcare facilities should recommend 2 doses of MMR vaccine at the appropriate interval for unvaccinated healthcare personnel regardless of birth year who lack laboratory evidence of measles immunity or lack laboratory confirmation of disease 10 .
- Exposed healthcare personnel without presumptive evidence of immunity should receive post-exposure prophylaxis, in accordance with CDC and ACIP recommendations. They should also be excluded from work from the 5th day after their first exposure through the 21st day after their last exposure, regardless of receipt of post-exposure prophylaxis. Further guidance on management of exposed or infected healthcare personnel is available on the CDC website.
Management of Patients with Suspected or Confirmed Measles
Measles Diagnosis and Clinical Characteristics
Measles is an acute viral respiratory illness characterized by fever, malaise, cough, conjunctivitis, a pathognomonic enanthema (Koplik spots) on the buccal mucosa, followed by a maculopapular rash. The incubation period for measles, from exposure to fever, is usually about 7–10 days. The rash usually appears about 14 days after a person is exposed. The rash spreads from the head to the trunk to the lower extremities. Patients are contagious from 4 days before to 4 days after the rash appears. Of note, some immunocompromised patients do not develop the rash 3 . Pregnant patients may also present with fever and elevated liver enzymes more often than nonpregnant patients 8 . For more information, see the CDC’s video resource on identifying and diagnosing measles under Additional Resources.
Measles Infection During Pregnancy
Measles infection in pregnant individuals is associated with several adverse events including increased risk of hospitalization, pneumonia and death 8 . Measles infection during pregnancy is also associated with significant risks to the fetus, including:
- Miscarriage
- Stillbirth
- Low birth weight
- Increased risk of preterm delivery 8
Notifying Health Departments
Obstetrician-gynecologists should first notify their local and/or state public health departments of any suspected measles cases. Health departments will provide guidance on testing, isolating and managing exposed patients or those suspected of having measles.
Testing and Reporting
Clinicians should follow the CDC’s testing recommendations and collect either a nasopharyngeal swab or throat swab for reverse transcription–polymerase chain reaction, as well as a blood specimen for serology from all patients with clinical features compatible with measles.
Clinicians should notify their local and/or state health department of any confirmed measles case. Clinicians may also consult with a local infectious disease expert for additional guidance.
Isolation
Obstetrician–gynecologists should advise nonpregnant and pregnant patients with suspected or confirmed measles to immediately isolate.
Postpartum patients with suspected or confirmed measles should also immediately isolate; however, clinicians should allow for shared medical decision making with the family for location of the infant after birth if the postpartum patient is infectious. Depending on the location of the infant, breastfeeding or feeding expressed breastmilk is beneficial. There is no contraindication to breastfeeding if a mother has measles.
Isolation should continue for four days after the patient’s rash develops (day zero). Within healthcare settings, patients with suspected or confirmed measles should be placed in an airborne infection isolation room (AIIR) and healthcare personnel should adhere to Standard and Airborne Precautions when caring for these patients until four days after initial rash development. Regardless of presumptive immunity status, all health care staff entering the room should use respiratory protection that is at least as protective as a fit-tested, NIOSH-approved N95 respirator.
If co-locating mother and infant, to reduce the risk of transmission to the infant, postpartum patients with measles may consider using source control, such as a NIOSH-approved disposable N95 respirator, to prevent spread of secretions; however, data are not available to inform this practice.
If the mother and infant are separated, they will also need to be on AIIR precautions as they are exposed. There may also be the need to transfer the infant to a higher level of care in which case separation would occur and AIIR precautions would also be necessary.
For cases in which a pregnant patient with suspected or confirmed measles is preparing for a cesarean delivery, clinicians should coordinate with the hospital to determine the right location for delivery as well as airflow considerations to limit transmission to other patients.
Treatment
There is no specific antiviral therapy for measles. Medical care is supportive to help relieve symptoms.
Vitamin A
Vitamin A does not prevent measles and is not a substitute for vaccination, nor does vitamin A treat measles alone. Although Vitamin A can be given under a provider’s supervision as supportive care for infants and children with diagnosed measles, there are no recommendations for use in other populations. Taking excess preformed vitamin A (found in liver and some supplements) before and during early pregnancy triples the risk of birth defects. Vitamin A from plant-based sources (e.g., specified as beta-carotene on supplement labels and in foods like carrots) are unlikely to cause harm. Pregnant people and people who may become pregnant should not consume more than 10,000 IU of preformed vitamin A per day without consulting a health care provider.
Postexposure Prophylaxis
Pregnant and nonpregnant people exposed to measles who cannot readily show that they have evidence of immunity against measles should be offered postexposure prophylaxis 11 .
Non-pregnant Patients
For nonpregnant patients exposed to measles who cannot readily show that they have previously received two doses of the MMR vaccine, obstetrician–gynecologists should administer either the MMR vaccine within 72 hours of initial measles exposure or immunoglobulin within six days of exposure. Do not administer MMR vaccine and immunoglobulin simultaneously, as this practice invalidates the vaccine 11 .
Pregnant Patients
For pregnant patients exposed to measles but without immunity, clinicians should administer intravenous immunoglobulin treatment (IVIG) at 400 mg/kg within six days of measles exposure.
Postpartum Patients
For postpartum patients exposed to measle who cannot readily show evidence of immunity against measles, offer postexposure prophylaxis via the MMR vaccine within 72 hours of exposure.
Infants
Infants born to pregnant patients with suspected or confirmed measles should be given postexposure prophylaxis with IV immunoglobulin (IVIG), as the mother with measles can be infectious for up to four days after the rash appears.
When indicated by health departments, infants 6–11 months of age may receive an early MMR vaccine dose. Subsequent doses should follow CDC’s recommended childhood schedule.
For additional information, please check the Centers for Disease Control and Prevention’s (CDC) Measles Cases and Outbreaks webpage.