Screening for Vaccine-Preventable Diseases 

Before you conceive, it is advisable to get yourself screened for vaccine-preventable illnesses. Should you contract any of these diseases during pregnancy, they could have a serious impact on you and your baby’s wellbeing.

These diseases include:

Once you are up to date with your vaccinations, you can proceed with your plans to conceive.


Get yourself vaccinated at least three months before pregnancy if you are not immunised against these diseases. 

Rubella (German measles)

Rubella is very contagious. It spreads when you breathe in droplets of respiratory secretions exhaled by an infected person. The Rubella virus causes fever and a rash that starts on the face and spreads to the body, and then to the arms and legs.

Rubella is not serious in children, but it can become very serious to foetuses, especially in the first four months of pregnancy. The risk of the mother passing the infection to the baby can be up to 90% in the first trimester (first 12 weeks of pregnancy). Heart damage, blindness, deafness and mental retardation may develop in the baby. The mother can also have a miscarriage or even a stillbirth.

Fortunately, rubella is no longer common because most babies are immunized against it as part of the MMR (measles, mumps, rubella) vaccine when they are 12 months old.

Chicken Pox Infection (varicella zoster)  

Like rubella, chicken pox is very infectious. As with the rubella virus, the Herpes zoster virus spreads when you inhale droplets of respiratory secretions exhaled by an infected person. 

A non-immunised person may catch chicken pox by being in the same room with an infected person. Symptoms may not appear until ten days to three weeks after infection. The patient often has fever and lethargy, followed by an itchy rash of watery blisters. The blisters will burst after a week and form crusts before healing. 

Chicken pox is uncommon in pregnancy. If it does occur in pregnancy, most women and baby suffer no serious effects. However, in one in two out of every 100 cases, the baby may be affected by skin blisters, scarring or even organ damage, especially in the first five months of pregnancy. These abnormalities may not be detected with ultrasound scans during pregnancy. They may only be diagnosed after the baby is delivered. Some pregnant women may also develop serious forms of infection in the chest or brain. 

If the baby is born within seven days of the mother developing chicken pox, he/she may get a very severe form of the illness. 

All it takes is a simple blood test to check if you are immune to the chicken pox virus. If you are not immune, get yourself vaccinated before you conceive.

​​​Hepatitis B ​

Hepatitis B is a liver infection caused by Hepatitis B viruses. The infection can be acute or chronic. Most chronic carriers have no symptoms. You can become infected by Hepatitis B through sexual contact or by exposure to infected body fluids such as saliva. 

If you are a chronic carrier of Hepatitis B, you can pass the infection to your baby. Infected infants do not appear to be at a higher risk of birth defects.   However, they have a 25% chance of dying from liver-related diseases such as chronic hepatitis, cirrhosis, and liver cancer later in life. 

To prevent the baby from being infected, he/she should be vaccinated with an injection of the Hepatitis B vaccine and anti-bodies immediately after delivery. Once the baby is vaccinated against Hepatitis B, the mother can continue to breastfeed even if she is a carrier

Frequently Asked Questions

1. Does vaccination carry any risks for the developing foetus?

There is no evidence that vaccinating pregnant women poses any risk to the developing foetus. The pregnant woman may be vaccinated with “killed” (inactivated) viruses, bacterial vaccines or toxoids. Examples of “killed” vaccines are flu, Hepatitis B and tetanus vaccines. 

We recommend that you avoid “live” virus vaccines (like measles, mumps, and rubella) that contain small parts of the actual virus. They may cause miscarriage or birth defects if they are transmitted to the baby. This risk is very small though. 

Other examples of “live” virus vaccines include chicken pox, smallpox, Bacillus Calmette-Guerin (BCG) and poliomyelitis vaccines.

2. Once I get a “live” virus vaccination, how long do I need to wait to

attempt to conceive?

If you receive a “live” virus vaccine, you need to wait at least three months before you try to conceive. Your body will need time to flush out the injected viruses.

However, if you become pregnant accidentally before the three months’ period, do not be alarmed. Consult your obstetrician immediately. The risk of your baby being affected is very small and you may not need to terminate the pregnancy.

3. Can I get other childhood diseases again?

Chicken pox, German measles and mumps generally give you a lifelong immunity once you have had them. If you are unsure of your immunity status, consult your obstetrician to do a simple blood test.

4. Is it safe for me to get a flu vaccine during pregnancy?

Getting the flu while pregnant may lead to complications in some women. These include high fever and lung infections, which may require hospitalisation.

It has also been suggested that flu may increase the rate of miscarriage. The flu vaccine can be safely administered to pregnant women to prevent these complications, especially during the flu season.

5. I seem to get more colds and flu than usual since my pregnancy began. Why is this so?

Pregnant women tend to get more colds and flu due to the weakened immune system during pregnancy. The body has to lower its defenses to make sure that the baby is not rejected. Unfortunately, pregnant women then become more susceptible to minor flu and colds than before.

6. Which travel vaccine is safe and recommended for pregnancy?

You can consider meningococcal and rabies vaccine if these diseases are endemic in the country which you are traveling to.

The safety of vaccines for yellow fever, Hepatitis A and typhoid is not yet established in pregnancy.

7. Are vaccinations safe for breastfeeding?

Be rest assured that vaccinations are safe for breastfeeding for both the “live” as well as inactivated vaccines.


Source: Dr TAN Thiam Chye, Dr TAN Kim Teng, Dr TAN Heng Hao, Dr TEE Chee Seng John, The New Art and Science of Pregnancy and Childbirth, World Scientific 2008.

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