Mumps is a contagious viral infection most commonly resulting in  painful swelling of the parotid salivary glands,These are found at the side of the face under the ears, giving the patient a unique “hamster face”. There is a good chance that you are immune to mumps, as children have been getting vaccinated with the two-dose MMR (measles, mumps, rubella) vaccine since the 1980s.  However, mumps outbreaks can still occur among unvaccinated people and among those who live close together, such as at universities or other close-knit settings.¹ 

The immune system of a pregnant person is often weaker compared to a non-pregnant person, making them more susceptible to infections such as mumps.² This article will detail how mumps is transmitted, the symptoms and potential complications of the infection, as well as the appropriate way to diagnose and treat mumps during pregnancy.   

How is mumps transmitted?

Mumps is caused by a virus known as the Rubulavirus in the paramyxoviridae family.³ TheRubulavirus typically replicates in the upper respiratory tract of a patient, which includes the mouth, the throat, the nose and the voice box. It is then commonly spread from person to person through direct contact through an infected person’s saliva, for instance from kissing, or by breathing in respiratory droplets that travel through the air when a patient has sneezed or coughed. Mumps can also be transmitted when touching surfaces and items, such as utensils and furniture, that an infected person has previously touched, or coughed and sneezed on.⁴ 

Infected individuals are contagious and can spread mumps to others from 2 days prior to the onset of symptoms, until roughly 9 days after the onset of symptoms. Once exposed to the virus, it can take 14 to 18 days before becoming symptomatic. The longer the time and the closer the contact with an infected person, the higher the risk of transmission of the mumps virus.⁴  

The way mumps is transmitted from person to person remains the same for both pregnant and non-pregnant people. However, due to the weakened immune system in a pregnant woman , they are more easily going to contract the virus and develop symptoms faster.²

Common symptoms of mumps

The classic hallmark symptom of mumps, which manifests in over 70% of all patients, is the painful inflammation and swelling of one or both of the parotid glands, located below the ear. This is also known as parotitis. The swelling typically reaches a peak roughly 3 days after its first appearance, and then decreases in size and pain during the following week.¹ 

Other common symptoms of mumps includes: 

• Fever
• Headache
• Fatigue
• Aching of muscles
• Loss of appetite
• The inflammation and swelling of other salivary glands found under the floor of the mouth (known as the submandibular and sublingual glands) - this occurs in 10% of all mumps patients
• Temporary hearing loss (occurs in roughly 1 in 25 patients) - Permanent hearing loss is incredibly rare (occurs in an estimated 1 in 20,000 cases)¹

Potential complications associated with mumps

Although significantly less common now due to herd immunity, there are further complications associated with mumps. Although they can be worrying, most of them clear up once the mumps infection passes. If a pregnant person develops such complications, this could affect their pregnancy. These include the following:

• Oophoritis - This is the inflammation and swelling of the ovaries, which can lead to pain in the lower abdomen, a fever and a general malaise. This type of inflammation does not commonly affect pregnancy, and it typically clears up once the mumps infection passes. However, for people who are trying to get pregnant, oophoritis could affect their fertility, as the inflammation could result in the production of scar tissue and blockages, stopping normal ovulation.⁵ 
• Acute pancreatitis - This is the inflammation of the pancreas, which results in sharp pains in the centre of the abdomen, diarrhoea, loss of appetite, fever and nausea. If a pregnant person with mumps does consequently develop short-term pancreatitis, this increases the risk of giving birth early (preterm labour) and foetal death.⁶ 
• Encephalitis - This is the infection and inflammation of the brain. This condition is very rare, occurring in roughly 1 in 1000 cases of mumps. Symptoms include fever, headaches, stiffness in the neck, disorientation and sensitivity to light and sound. Encephalitis must be taken seriously, as it could potentially be fatal. Hence, if one experiences this condition, they must be admitted to the intensive care unit of a hospital.⁷ Pregnant mumps patients who develop encephalitis could be more at risk of having a miscarriage or preterm labour. However, fortunately, most newborns of people who had encephalitis during their pregnancy tend to have no health complications themselves.⁸ 
• Viral meningitis - This is when the Rubulavirus spreads to the outer protective layer of the brain called the meninges, leading to their inflammation. This complication occurs in roughly 25% of mumps patients. Not to be confused with bacterial meningitis which can be fatal, viral meningitis results in flu-like symptoms which typically last 14 days, with low risk of serious complications. This condition also has little-to-no effect on the health of both the pregnant person and their foetus.⁹ 

Do mumps cause further risks in pregnancy?

Whilst it is possible for any virus to have adverse effects on pregnancy, mumps is generally not more severe in pregnant people compared to non-pregnant people (besides the potential complications outlined above). Only one study conducted in the 1960s (when the mumps vaccination was not available and hence the virus was more common) found that being infected with mumps during the first trimester of pregnancy increased the risk of a miscarriage or foetal death.¹⁰ However, besides this, no other studies found such association.¹¹ 

In addition, no studies have found the mumps virus to be teratogenic, which means that the virus does not affect the DNA of the foetus, meaning mumps is not associated with an increased risk of congenital disorders.¹⁰ 

Other possible rare risks for pregnant people with mumps, which have been found from case study reports, include:

• A possible association was found between mumps during pregnancy and endocardial fibroelastosis, a foetal and infant heart condition which results in the thickening of the heart muscles.¹² 
• Developing mumps during the final weeks of pregnancy may also be associated with acute respiratory distress and thrombocytopenia in the baby.^13,14 

Diagnosis of mumps

If one suspects that they have mumps, in order to identify and diagnose the infection they must visit a doctor. The doctor first assesses a patient’s symptoms — hallmark signs they look out for including parotitis and checking for a fever. 

If a doctor suspects a patient does have mumps from assessing symptoms, the patient will then give a sample of their saliva, and this sample will then be used in laboratory tests in order to confirm or rule out mumps as a diagnosis. The most common and preferred laboratory test is the RT-PCR test, which is able to detect whether the mumps Rubulavirus is present in the patient’s saliva. Important factors to take into account when interpreting a patient’s RT-PCR results is if and when the patient has been vaccinated against mumps. For instance, if a patient recently got vaccinated, then this could lead to a false positive result, as the test is instead detecting the vaccine rather than an infection. 

The way mumps is diagnosed remains the same for both pregnant and non-pregnant people.

Management and treatment of mumps during pregnancy

Although there is no specific treatment for mumps, there are various ways in which pregnant people can manage mumps and alleviate symptoms:

• Medications - Prior to taking any medicine to lessen mumps symptoms, it is imperative for pregnant people to check with their doctors which medications they can safely take without affecting their pregnancy and their foetus. For instance, paracetamol is generally safe for pregnant people to use, and is an effective medicine to relieve pain from swollen glands and to lower a fever. Examples of pain medications to avoid, on the other hand, include NSAIDs (past 20-30 weeks of pregnancy) and high doses of aspirin.
• Cold compresses - By applying a cold compress to swollen glands, it helps provide pain relief. 
• Drinking plenty of water and eating soft foods - This will make it easier for the patient to swallow food whilst having swollen glands. 

How to prevent getting mumps whilst pregnant?

MMR vaccine

The best way to prevent mumps is by getting the MMR vaccination — the two-dose vaccine has been found to be 88% effective in preventing the spread of the virus. Not only does the MMR vaccine prevent someone from catching mumps, it also reduces the chances of a patient suffering from severe symptoms, resulting in a quicker recovery from infection.

However, it is important to note that getting the MMR vaccine done whilst pregnant is not advised. This is because this vaccination is a live attenuated vaccine. This type of vaccination consists of giving a patient a weakened version of the virus, which means the virus cannot properly infect the patient, but the immune system can build a defense against it. There is the worry that, if you get a live attenuated vaccination such as the MMR vaccine whilst pregnant, the weakened virus could cross the placenta and initiate a viral infection in the foetus.¹⁵ Hence, it is best to avoid getting the MMR vaccine (if not already given) if you are pregnant. 

If one is planning to get pregnant and has not yet been vaccinated against mumps, then it is advised to get a MMR antibody screening test done to check whether they already have natural immunity against mumps (from prior infection). If one is not immune to mumps, then it is advised that they get the MMR vaccine, and then avoid getting pregnant within the next month, so the vaccination then has no adverse effects on the foetus.¹⁵ 

Standard hygiene practices

Like with other infections, keeping standard hygiene practices will help prevent the spread of mumps. This includes:

• Washing hands often
• No sharing of food, drink, and cutlery
• Coughing and sneezing into own elbows
• Cleaning surfaces after coughing and sneezing on them, such as kitchen surfaces
• Throwing away tissues immediately after usage  

Summary

Mumps is a viral infection which leads to the painful swelling and inflammation of the parotid glands, and subsequent symptoms of fever, headaches, and a general malaise. The virus is typically spread through contact with an infected person’s saliva and respiratory droplets. Mumps does not commonly lead to severe adverse effects in pregnant people and their foetuses. Rare potential complications of mumps during pregnancy include the development of oophoritis, acute pancreatitis or encephalitis, increasing the risks of preterm labour and miscarriages. In addition, other rare risks include the development of endocardial fibroelastosis, acute respiratory distress and thrombocytopenia in the foetus. If a pregnant person suspects they have developed mumps, then they are advised to visit a doctor who will diagnose the infection by assessing their symptoms, and collecting a sample of their saliva to confirm the presence of the virus via laboratory tests. Once diagnosed, they can take safe medications prescribed by a doctor, such as paracetamol, in order to alleviate any pain. Patients can also use cold compresses, drink lots of water, and eat soft foods in order to help lessen symptoms. The best way to prevent getting mumps is to get vaccinated with the MMR vaccine. However, it is strongly advised to get vaccinated at least a month prior to becoming pregnant, as being vaccinated whilst pregnant could lead to an infection in the foetus.