Introduction

Measles is a highly contagious disease caused by morbillivirus. This disease is airborne and spread via an infected person's transmission of droplets, such as when they breathe, talk, cough or sneeze. It can pose a significant health risk, particularly for pregnant people and their fetuses. Infection with measles can increase the chances of miscarriage and increase the chance of foetal death after 20 weeks, known as stillbirth.

Although rare, near the time of delivery, there may also be an increased chance of the baby being born with measles. Understanding and educating ourselves on the implications of measles during pregnancy and the effects impacting foetal development and outcomes is important.

Understanding measles

According to the WHO (World Health Organisation), measles is a highly contagious airborne disease caused by a virus that can lead to severe complications and death. The virus is known as the measles virus or morbillivirus. The virus can be transmitted when released into the air when you breathe, cough or sneeze.

Once inside the body, the virus infects the respiratory tract and spreads throughout the body. It can also remain infectious on surfaces, typically for up to two hours. As the virus is highly contagious, when infectious particles enter the air and adhere to surfaces, anyone who comes into contact with the virus (and is not immune to it) may become infected.¹

The first sign to look out for if you suspect measles is a high fever occurring 10-12 days after exposure to the virus, lasting 4-7 days.

Early-stage symptoms, typically lasting 4-7 days, include:¹

• Cough
• Runny nose
• Red and watery eyes
• Small white spots inside the cheek

After 7-18 days after exposure, a prominent rash will begin usually on the face and upper neck. The rash will spread over three days, eventually reaching the hands and feet, and usually lasting 5-6 days before fading.

The impact of measles on pregnant patients

Measles can put pregnant people at risk, as it may cause them to go into early labour - increasing the risk of their baby having a low birth weight and of stillbirth. Although rare, there is also a risk of a baby being born with the virus.

Measles infections can cause severe complications and significantly impact pregnant people’s lives. These complications can include:^1,2

• Blindness
• Encephalitis (irritation and inflammation of the brain) which can cause permanent brain damage
• Severe diarrhoea, which can lead to dehydration
• Ear infections: most commonly a bacterial ear infection
• Bronchitis, laryngitis or croup - caused by inflammation of the croup and inner walls that line the main air passageways of the lungs, as well as the inflammation of the laryngitis
• Severe breathing problems, like pneumonia

Prevention in pregnant patients

To avoid contracting measles some preventative actions can occur to gain immunity and to protect yourself. It can primarily be achieved through vaccination of the measles, mumps, and rubella (MMR) vaccine, by using a weakened or inactive part of an antigen that will trigger an immune response from the body. According to the CDC, one dose of MMR vaccine is 93% effective against measles while two doses of MMR vaccine are 97% effective against measles.³

Individuals assigned female at birth (AFAB) who are of childbearing age and do not have presumptive evidence of immunity should check with their doctor to make sure they are vaccinated before they get pregnant. The Centers for Disease Control and Prevention (CDC) recommends that individuals receive the measles, mumps, and rubella (MMR) vaccine at least one month before becoming pregnant, as 1) the vaccine may cause complications to arise and 2) pregnancy is a contraindication for the MMR vaccine. Getting vaccinated helps ensure the pregnant parent can transfer protective antibodies to the foetus for immunity. 

Maintaining your immunity during pregnancy is important; however, receiving the MMR vaccine during pregnancy is not recommended. Protect yourself and avoid others who are sick with these diseases by practising good hygiene, such as washing your hands well with soap and water.

Preventing new measles infections

Getting vaccinated with the measles vaccine is important for:

• Preserving and promoting herd immunity: herd immunity is achieved when a large percentage of a community is vaccinated against a given disease, reducing its overall prevalence. Since the measles vaccine was introduced, measles has been eliminated from the UK³ 
• Preventing a resurgence of measles cases: maintaining steady vaccination rates is crucial to prevent resurgences of cases and a loss of herd immunity

Preventing measles during an outbreak

If someone close to you or in the same household has measles, take these precautions to protect those who are vulnerable and without immunity:

• Isolate: measles is highly contagious for about four days before to about four days after the rash appears, those who have caught measles should stay home and not interact with the general public to protect others
• Vaccinate: ensure those in high-risk groups such as infants older than 6 months and anyone born in 1957 or after or with no proof of immunity, get vaccinated against measles as soon as possible

Management of measles in pregnant patients

Pregnant patients with unconfirmed measles or who suspect they are infected measles should isolate themselves. The isolation should occur for 4 days after the rash develops. Serological testing on blood specimens from all suspected patients with measles should be completed. According to the American College of Obstetricians and Gynecologists, pregnant patients who are exposed to measles, but who have not received the MMR vaccine, should be offered postexposure prophylaxis.

Pregnant patients who are thought to have been recently exposed to measles should receive Human Normal Immunoglobulin (HNIG) (antibodies) via intramuscular injection within six days of exposure. This will reduce the rate of complications associated with measles.

Challenges and misconceptions

Although the MMR vaccine has been proven safe and effective, misconceptions about vaccines and vaccine hesitancy remain a challenge to eliminating measles. Public perceptions of vaccine safety and vaccine uptake are often fueled by misconceptions. One important example was a now-discredited study conducted in the UK in 1998 which inaccurately linked the MMR vaccine to autism.

After the publication of this case study, the rate of vaccination in the UK dropped to an all-time low, with just 80% of children being vaccinated between 2003 and 2004. This led to a reduction in herd immunity. Besides the UK, other countries also experienced a drop in vaccine uptake due to the belief in this potential link.⁴

However, more recent reports from several journals - including the American Academy of Pediatrics, the National Institute of Health - conclude that there is no scientifically proven link between the MMR vaccine and autism.^5,6 Ongoing education of the public on the importance and implications of the MMR vaccine can help gain or rebuild the trust and understanding of the public, particularly for people of childbearing age.

Summary

Measles poses a significant risk to vulnerable groups - including pregnant people and their foetuses. For pregnant people, measles can lead to severe complications, including miscarriage, stillbirth, and low birth weight. Early-stage symptoms to look out for include a high fever, cough, runny nose, and rash.

Pregnant people especially face risks with more serious conditions like encephalitis and ear infections. To prevent measles, receive at least one dose of the MMR vaccine to help maintain herd immunity and prevent outbreaks. Vaccination is also essential for community protection.

People of childbearing age should be vaccinated at least one month before conception to ensure that protective antibodies are transferred to the foetus. Encouraging and offering evidence-based information regarding vaccinations can tackle misconceptions and promote the benefits of MMR vaccine benefits, both for individuals and society as a whole.