Blood tests in pregnancy

During pregnancy, you will be offered blood tests to check you and your baby are healthy.

By having the tests as soon as possible during pregnancy, you can have treatment for any conditions or diseases that could affect your or your baby's health.

The tests

When you see your midwife or specialist doctor for the first time about your pregnancy, they’ll offer you these 7 tests. The tests are free and are taken from 1 blood sample.

Full blood count

This blood test checks whether your body has enough iron during pregnancy. If your iron levels are low, you will feel more tired and be less able to manage the blood loss that happens during birth. You will be offered advice about how to increase the iron in your diet and/or given iron tablets.

The test also checks your platelet levels and white cells. Platelets help your blood to clot, while a lot of white cells can be an indication of an infection.

Blood group and antibodies

This test checks your blood group and for the presence of antibodies (part of your immune system). Your blood group can be A, B, O or AB.

Some antibodies can be harmful for your baby during pregnancy. If you do have antibodies that could affect your baby, monitoring and treatment are recommended.

Rhesus factor

One of the antibodies that will be checked is your rhesus factor (mainly Rh D). You are either Rh positive (Rh+) or Rh negative (Rh-).

If you are Rh- and your blood mixes with your baby’s blood you can make antibodies which can cause severe anaemia and jaundice in this or your next baby. Your blood can only mix with the baby’s if you bleed during pregnancy, a miscarriage or termination, or during the birth. An injection of ‘Anti-D’ after any of these events can prevent your body from making these potentially harmful antibodies. Find out more at Problems in the week after the birth.

Rubella (German measles)

This test checks whether you are immune to (protected against) rubella, also known as German measles. If you catch the rubella virus in pregnancy it can lead to severe problems for your baby (eg, deafness or brain injury) or miscarriage.

If you are not immune, you can have a vaccination called MMR to prevent problems in future pregnancies. This vaccination can only be given when you are not pregnant.

Hepatitis B

Hepatitis B is a virus that can be passed to a baby during birth. You may have this disease but not know because there are often no symptoms. Hepatitis B can cause significant health problems, including liver damage. About 20% of babies exposed to hepatitis B during birth, and left untreated, become infected. Over 90% of untreated babies become carriers of the virus.

If have hepatitis B you will be offered immunoglobulin and vaccination at birth for your baby to help prevent your baby becoming infected. For more information about hepatitis B go to the Hepatitis Foundation website.


Human immunodeficiency virus (HIV) affects your body’s ability to fight infection and can cause AIDS. HIV is passed on to others by contact with blood or body fluids.

If you have HIV, it can be passed on to your baby during pregnancy, birth or breastfeeding. New medicines can protect your baby and help you to stay well.

To find out more, go to HIV testing in pregnancy.


Syphilis is a rare infection in New Zealand, but it is becoming more common. Most women with syphilis do not know they have the disease because they feel well and have no symptoms.

If left untreated, syphilis can cause serious health problems for you and your unborn baby. It can be passed on from mother to baby during pregnancy. A blood test in early pregnancy, and treatment if needed, can help to avoid these problems.


Diabetes is when you have too much sugar in your blood. Many people do not know they have diabetes and have no symptoms. During pregnancy it can make you sick and affect your baby’s growth. If you already have diabetes or you develop diabetes in pregnancy, you will be offered information, treatment and support – including help to eat well and stay active.

Diabetes testing is offered twice in pregnancy. The first test checks if you have diabetes or are prone to developing diabetes. The later test tells you whether you are developing diabetes while you are pregnant. To find out more, go to Testing for diabetes in pregnancy.

Your results

Your results will be available from the health practitioner who organised your blood tests. You can also request the result from your doctor, nurse or midwife.


All of your pregnancy blood test results, including HIV, will be sent in confidence to your GP, midwife and to your local district health board (DHB) where you will give birth.

Your personal details are carefully protected. Details that could be used to identify you are not be used in national reporting.

Further information

If you would like more information about these or other screening tests/programmes, or need to have information in a different language, please ask your midwife, GP or specialist.

Having testing is your decision

Before having any blood tests you will be offered information about the tests. This allows you to make a decision that is right for you and your baby.

The decision to have these blood tests is yours and will be respected. If you have any questions, ask your midwife, GP, nurse or specialist.

The Ministry of Health recommends that you have these tests as soon as possible after you know you are pregnant. Knowing whether you have these conditions can help keep you and your baby well.

In this section

  • Diabetes can cause problems for you and your baby during your pregnancy and birth, so it’s important to know if you have or are at risk of diabetes and how to look after yourself and your baby. Read more
  • HIV is a virus that can make you and your baby sick. You will be offered a free HIV blood test when you have your first blood test during pregnancy. Read more
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