Hepatitis B and pregnancy

Hepatitis B is a viral infection that causes inflammation of your liver. If you have hepatitis B during pregnancy, you can pass the virus on to your baby. Vaccinations and treatment after the birth can protect your baby from infection.

During pregnancy, as part of  your antenatal checks when you first see your family doctor, midwife, or specialist doctor, you will be offered a blood test to test for hepatitis B. Most women who are carriers of the hepatitis B virus are unaware of this, because often there are no symptoms or only mild symptoms.

If your blood test is positive for hepatitis B, it is possible for you to pass hepatitis B to your baby during the birth through contact with your blood and body fluids. This can happen with vaginal delivery or caesarean section.

When young children and babies get infected, they do not tend to get sick but are at much higher risk of remaining a hepatitis B carrier and developing chronic infection later in life (life-long risks include cirrhosis, liver failure and liver cancer). Read more about hepatitis B

How to protect your baby from hepatitis B?

During pregnancy, if you test positive for hepatitis B, you will be offered a test that checks the level of hepatitis B virus in your blood. The level of hepatitis B is called the viral load. If your viral load is high, you may be offered daily treatment with an antiviral medication to reduce the risk of passing the disease on to your baby.

Hepatitis B vaccine and hepatitis B immunoglobulin

If your viral load is lower, your baby can be protected from the virus by giving your baby the hepatitis B vaccine and hepatitis B immunoglobulin (special antibodies) within the first 12 hours after birth. The immunoglobulin gives your baby immediate protection until the vaccine has time to work. This combination of medication is very effective – your baby has a greater than 95% chance of being protected against hepatitis B infection. Your baby will also need the usual hepatitis vaccine at 6 weeks, 3 months and 5 months of age. 

At 9 months of age, your baby will be given a blood test to check if they are protected against hepatitis B or have been infected with the virus. If your baby is not protected, a further 2 doses of the hepatitis B vaccine may be given.

Is it safe to breastfeed?

Mothers with hepatitis B can breastfeed safely.

What about side effects of the vaccine and immunoglobulin?

Like all medicines, hepatitis B vaccine and hepatitis B immunoglobulin can cause side effects, although not everyone gets them. Some of the possible side effects include a mild reaction to the injection such as a rash or a rise in body temperature and, rarely, a severe reaction to the injection.

Learn more

Hepatitis B – information for pregnant women HealthED, Ministry of Health, NZ
Hepatitis B and pregnancy Hepatitis Foundation, NZ


  1. Management of hepatitis B in pregnancy RANZCOG, 2016
  2. Hepatitis B vaccination Newborn Services Clinical Guideline ADHB, 2015
  3. Hepatitis B – information for pregnant women HealthED, Ministry of Health, NZ
Credits: Health Navigator Editorial Team.