Pennsylvania measles outbreak tops 1,000 cases, bringing pregnancy care into focus

The Centers for Disease Control and Prevention counted 3,887 confirmed cases across 47 jurisdictions as of Thursday, Oct. 1. The agency reported 42 outbreaks in 2026 and said 95% of confirmed cases were outbreak-associated. State and federal totals can differ because they are reported on different schedules.

Why does measles affect pregnancy care?

Measles during pregnancy can be associated with pregnancy loss, premature delivery and low birth weight, the American Academy of Pediatrics says. That makes it important for clinicians to assess a patient’s immunity and respond to a possible exposure with guidance suited to pregnancy.

Before pregnancy, clinicians can discuss vaccination and check whether a patient has evidence of immunity. Dr. Holly Cummings, a Philadelphia OB-GYN who chairs Pennsylvania’s section of the American College of Obstetricians and Gynecologists, told The 19th she is increasingly ordering blood tests for patients considering pregnancy rather than assuming they are protected based on vaccination history.

Two doses of MMR are 97% effective at preventing measles, the CDC says. ACOG advises clinicians to discuss vaccination with nonpregnant patients who do not have presumptive evidence of immunity. During pregnancy, however, MMR is not administered.

For a pregnant patient exposed to measles who lacks evidence of immunity, ACOG recommends offering intravenous immune globulin, a preventive treatment given after exposure. The advice depends on a patient’s circumstances; it is not a substitute for checking immunity before pregnancy or seeking clinical guidance after a known exposure. Susceptible patients may also be offered MMR vaccination after delivery.

Measles spreads through the air. The CDC says a person can become infected after entering a room where someone with measles has been, which is one reason exposure concerns can extend beyond the place where an outbreak began.

Dr. Sharee Livingston, an OB-GYN in Lancaster County, told The 19th: “Air doesn’t know that there’s a border between Pennsylvania and Ohio, or that there’s a border between New Jersey and New York.” The presence of cases in multiple jurisdictions does not mean every community or pregnant patient faces the same likelihood of exposure.

How can measles affect newborn care?

Care for a newborn may depend on when the birth parent became ill in relation to delivery. The AAP’s clinical guidance on congenital measles advises clinicians to consider immune globulin for newborns born within 14 days of the birth parent’s rash onset. Depending on the circumstances, care can also involve testing, supportive treatment and infection-control measures.

The timing matters to the risk estimate, too. AAP News summarized an estimated 25% to 30% infection rate for babies born to someone infected shortly before delivery. That estimate applies to this timing-specific situation, not to all pregnancies affected by measles or all newborns whose birth parent had the disease at some point during pregnancy.

Pennsylvania officials reported a measles exposure in September at locations in the Children’s Hospital of Philadelphia complex, including a lounge in a neonatal intensive care unit, The 19th reported. The episode underscores why hospitals and obstetric and pediatric teams need to coordinate exposure information and newborn care.

The state health department told The 19th it could not confirm an estimate of congenital measles cases or provide more details about infected pregnant people, citing privacy laws. It said it was working with the CDC on a system to track and report congenital cases. The department also said there was no nationally standardized definition for those cases.

AAP guidance describes decisions that can include monitoring and follow-up as well as supportive treatment, while acknowledging that evidence is limited for some recommendations. Dr. Pia Pannaraj, a pediatric professor at the University of California, San Diego, and a member of the AAP’s Committee on Infectious Diseases, told The 19th that clinicians need education about an illness many may never have treated.

Clinicians interviewed by The 19th also discussed early MMR vaccination for some infants from 6 months of age who live in or travel to areas with possible exposure. An early dose does not replace the later routine doses.

What does measles elimination mean?

The CDC defines elimination as at least 12 months without continuous transmission in a geographic area. The United States was declared to have eliminated measles in 2000. Elimination is not eradication: the virus can be reintroduced, and outbreaks can occur.

The national case count shows that measles remains a public health concern even after elimination. It does not establish that pregnant people across the country face comparable exposure. For clinicians, the practical questions remain whether a patient has evidence of immunity, whether an exposure occurred and when an infection happened in relation to delivery.

Dr. Kisha Davis, president-elect of the American Academy of Family Physicians, told The 19th: “Measles wasn’t a conversation we were having before, but it is now.” Her observation reflects the renewed need for clinicians to give patients reliable, pregnancy-specific guidance as cases occur.

Pennsylvania’s work with the CDC to develop congenital-case tracking is one step toward more consistent information for families and care teams. The immediate clinical decisions still turn on the timing of exposure, immunity and birth.