What Antenatal Screening Tests Are Done During Pregnancy?

    It’s important to attend routine antenatal screening tests during your pregnancy to check for anything that may cause a problem during your pregnancy or after birth. There are a number of antenatal tests available on the market, and at OT&P Healthcare, we offer screening tests according to international recommendations. 

    We believe that every pregnant woman deserves to have non-biased information regarding her care and childbirth options – so we have compiled a list of some standard & common antenatal screening tests that you may encounter. 

    Standard tests

    Other Tests

    Standard antenatal tests

    Below are the standard tests that pregnant women will take, and that we provide at OT&P: 

    Complete blood count

    This test assesses all components of your blood to look for anaemia, platelet counts, thalassemia and more. It’s usually done at the first visit, then at 28 weeks. The key things that doctors will look out for are your haemoglobin levels (red blood count) – to ensure that you are carrying enough iron and oxygen around your body and to your baby. Additionally, blood results can tell doctors if there are any underlying diseases present. 

    Blood type and rhesus blood group

    This form of blood test will determine your blood group (ABO) and rhesus status. The rhesus blood group is fixed by your genes and has two outcomes: 

    • Rhesus positive: a protein is found on the surface of your red blood cells.
    • Rhesus negative: you don’t have the antigen on your blood cells.

    When negative, your pregnancy will likely need extra monitoring to ensure you and your baby are developing in a healthy manner. 


    The antibodies test typically looks for atypical antibodies in the blood and is again, done at the first visit and later at 28 weeks. 

    The reason we screen for atypical antibodies is that they have the potential to cause harm to you or your developing baby. 


    Syphilis screening

    All women should be screened for syphilis during their pregnancy. Syphilis is a bacterial infection that can harm the baby’s health and development, but with little to no symptoms present. Syphilis in pregnant women can cause a range of issues, such as miscarriages, stillbirth, or the baby’s death after birth. Fortunately, it can be treated through medication but should do so as soon as possible!


    Hepatitis B

    This screening looks to see if the mother has hepatitis B. Although when positive, it doesn’t cause any problems during pregnancy (for mother and baby), your baby will need to be protected from the infection after it’s born – especially during breastfeeding. 



    Human Immunodeficiency Virus (HIV) is a virus that affects the body’s ability to fight foreign infection. Untreated and undetected, it can lead to AIDS (acquired immunodeficiency syndrome). A pregnant woman can pass HIV to their baby during pregnancy, birth or through breastfeeding – so it’s important to screen for it and treat it, as with treatment, the chance of the baby being born with HIV is less than 1 per cent.



    Testing for rubella will ensure that pregnant women have a sufficient amount of rubella antibodies to protect them and their baby against infection. Anyone who is not vaccinated against rubella has a chance of getting the disease and could harm the baby. 

    It’s therefore recommended that women who are planning to become pregnant check with their doctor and make sure they are vaccinated before getting pregnant. If unvaccinated and already pregnant, it’s usually advised that they do so after delivery. 


    Other antenatal screening tests

    These are some of the more common tests done in pregnancy. Depending on your individual circumstance, other tests may be necessary at various times in your pregnancy. In these situations, your doctor will discuss with you the rationale and process for the recommended tests. 


    Screening for Down Syndrome (trisomy 21)

    We offer and recommend non-invasive prenatal testing (testing for baby’s DNA in the mother’s blood) due to its higher sensitivity and specificity. The test can detect more than 99% of Down Syndrome babies. As part of this screening, trisomy 13 and 18 (Patau and Edwards’ syndrome) will also be screened. 

    It’s also possible to detect the baby’s gender with this test, so if you would like to keep it a surprise, please inform your doctor. 



    A high-quality first-trimester ultrasound within the initial 14 weeks of pregnancy is recommended to ensure the size of the baby is correct at this gestation. This is essential for women who have irregular menstrual cycles to ensure the estimated date of delivery can be accurately calculated. 

    A structural ultrasound can be done at 20–22 weeks to look at the baby’s organs in detail. At its best, an ultrasound at this gestation can detect up to 70% of abnormalities. But you should also tell your doctor if you have any personal or family history of congenital conditions. 


    Thyroid function

    Most women will find they are extremely tired in early pregnancy. In some situations, we will recommend screening the thyroid function to ensure they are not lacking thyroid hormones, which will affect the baby’s brain growth. This screening (along with urine culture for infections) will also be done if there is excessive vomiting (morning sickness) in pregnancy. 


    Oral Glucose Tolerance Test

    This is a screening test for diabetes in pregnancy. Most women will have it done between 24 to 28 weeks gestation. Women with certain risk factors will need to have it done a second time earlier on in the pregnancy (around 16 weeks). 


    Group B Streptococcus

    This is a screening test that is done at 35 to 37 weeks gestation to look for a bacterium called Group B Streptococcus. This bacterium normally resides in 25% of women and does not affect them. However, after the waters break or when in labour it can infect the baby and hence will require antibiotics.


    Pregnancy support in HK

    At OT&P, we advocate for tests with higher sensitivity in order to reduce a mother’s anxiety and unnecessary invasive testing. If you are looking for advice or pregnancy support, please feel free to reach out to our team.

    Additionally, we also provide a range of maternity packages tailored to giving birth in Hong Kong. We’ve carefully designed our packages to ensure peace of mind from the prenatal/antenatal stages to postnatal stages of your pregnancy. Packages can also be customised and tailored according to your individual needs.


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    Topics: Pregnancy

    OT&P Healthcare

    OT&P Healthcare

    OT&P Healthcare is a Premium Private Healthcare Practice in Hong Kong. Our priority is to help individuals to enhance and optimise their health by providing easy access to a wide range of excellent practitioners and information, supported by management systems and technology that ensure quality of service and value. Our Mission is to provide pre-eminent private healthcare in Hong Kong. We aim to be the best in class fully integrated healthcare service, providing a circle of care for all our patients' needs.