Blood Testing in Pregnancy

Posted on June 27, 2018 - 12:15pm
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Routine antenatal screening blood tests are performed early in pregnancy to determine if there are any underlying health concerns that may affect you or your baby during pregnancy. They are also conducted to determine your status of immunity for infections, which can be detrimental to the wellbeing of your baby. Finding these things out early allows for early management and/or treatment.


Blood Group and Antibody Screen:

It is important that your blood type is known, particularly whether you are a positive or negative type. If you are negative, it is helpful to also know your partner’s blood type as well. If you are negative, you will be given Anti-D injections at various stages of your pregnancy to avoid sensitisation (the baby’s blood cells causing an immune response in the mother).

Full Blood Count:
Allows a baseline of your blood to be obtained, which can be used for comparison in later pregnancy, and also for general review.

Thalassemia Screen: 
Genetic blood disorder screening. If you are found to be negative then no further tests are done. However, if you are positive then we will also screen your partner. If you are both found to be positive, genetic counselling will be undertaken.

Ferritin (iron) Studies: 
Are conducted to rule out anaemia. Your iron levels will be managed throughout your pregnancy, and supplements advised if required.

Rubella (German Measles)- & Varicella Zoster Virus (Chicken Pox): 
Are childhood illnesses, which can be dangerous to your baby. If you are not immune you will be advised to have a booster after the birth of your baby and be careful to keep away from people who may have contracted rubella or chicken pox.

Hepatitis B & C, HIV and Syphilis: 
Tests for infectious diseases that can be transferred to your baby. Allows for early management.

Thyroid Function:
Pregnancy hormones can affect thyroid function, which is important for maternal and fetal wellbeing.

Vitamin D:
Is important for bone density. If you are severely depleted in vitamin D, it can increase risk of ricketts in your baby. However, in most cases, supplementation will improve levels quickly. You will be advised if supplements are needed.

MSU+C (Mid stream urine which is cultured): 
Normal signs and symptoms of a urinary tract infection (UTI) can be masked by pregnancy, making it undetectable. Therefore, it is important to test via MSU. An untreated UTI is dangerous in pregnancy, and can bring on early labour. MSU also picks up other common potential infections.



FBC (Full Blood Count):
Is performed to test general wellbeing and compare with your initial FBC test.

Iron (Ferritin) Study:
Iron levels are tested again to manage iron deficiency (anaemia), which is common in pregnancy and leading up to the 3rd trimester. A supplement will be advised if you are found deficient. The aim is to have iron within normal ranges by around 37 weeks gestation prior to birth.

Red Cell Antibody Screen:
Tested again to review, and make sure there have been no changes to antibody status since initial screening bloods were taken.

Full Glucose Tolerance Test (FGTT)
The full glucose tolerance test (FGTT) is done to detect gestational diabetes mellitus (GDM); diabetes brought on by pregnancy. The FGTT is now routinely screened for in pregnancy. If you have risk factors, such as a family history of diabetes, PCOS, twin pregnancy, previous GDM or aged 40 yrs and over, you will be offered the FGTT test around 18 weeks and then repeated at 28 weeks. Gestational diabetes is a very manageable condition, and you will be referred to an endocrine specialist and dietitian who will work alongside Dr Morris to manage your pregnancy and delivery.



You may be required to retest for routine management and review, and usually only if you had low iron levels or concerns at the 28 week blood testing.


Iron (Ferritin) Study (if you have had low iron throughout your pregnancy and were supplemented on extra iron) to ensure good levels prior to birth.

Antibody (if you have a negative blood type)


If you have specific health conditions or requirements, other tests may be performed throughout your pregnancy. Likewise, if conditions arise throughout your pregnancy, investigations other than those listed here may be undertaken. If you have further questions relating to these tests, please discuss at your consultation with Dr Morris or the midwives at your next visit.

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early pregnancy   iron   pregnancy supplements   routine blood testing   screening tests  
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