Paternity testing while pregnant

Casey Randall AlphaBiolabs

By Casey Randall, Head of Genetics at AlphaBiolabs

Last reviewed: 20/04/2023

Prenatal DNA paternity testing makes it possible to identify whether a man is a baby’s biological father before the baby is born.

In other words, the DNA test is performed while the mother is still pregnant.

In this guide, we provide a full breakdown of everything you need to know about prenatal DNA paternity testing, how it works and when you should consider taking a test.


How does a prenatal paternity test work?

The testing process for prenatal DNA paternity testing is based on the same principle as a standard DNA paternity test.

By examining the baby’s DNA together with the parents’ DNA, it is possible to identify which half of the DNA is inherited from the mother and which half is from the father.

If the tested man in indeed the biological father of the baby, both will share DNA. When the tested man is not the biological father, there will be differences in the DNA of the man and the baby.


Can I get a paternity test while pregnant and is it safe?

The first question that many people ask about prenatal paternity testing is ‘can I get a DNA test while pregnant?’

The simple answer is, yes.

AlphaBiolabs’ prenatal paternity testing is non-invasive and uses cheek (buccal) swabs from the alleged father and the mother (pregnant woman), along with a blood sample from the mother to determine whether the man is the biological father of the child.

A blood sample is only needed from the mother, which is taken from her arm, and no needles need to be inserted into the womb. As a result, there is no risk to the mother or the unborn child when taking this test.


What is a non-invasive prenatal paternity test (NIPP)?

A non-invasive prenatal paternity test is the safest and most accurate way to establish paternity during pregnancy.

Unlike other tests which involve taking cells from the placenta (chorionic villus sampling or CVS test) or extracting a sample of amniotic fluid (amniocentesis), all that is required for a NIPP test is a blood sample from the mother, and cheek (buccal) swabs from the mother and alleged father.

A NIPP test is the only prenatal paternity test that poses zero risk to mum or the unborn baby.


How early can I do a paternity test?

A prenatal DNA paternity test can be performed as early as seven weeks into the pregnancy, or nine weeks since the mother’s last period.


How is a prenatal paternity test done and what samples are required?

To perform a non-invasive prenatal paternity test, we need to look at three samples:

  • The man’s DNA (alleged father) – collected using cheek swabs
  • The pregnant woman’s DNA – collected using cheek swabs and a blood sample and
  • The unborn baby’s DNA – identified via the mother’s blood sample

The baby’s DNA is passed into the mother’s bloodstream via the placenta during pregnancy. The test is performed by analysing the baby’s DNA and comparing DNA markers to that of the parents.


How are the samples collected?

It’s important to note that a prenatal paternity test cannot be performed without the consent of all parties involved in the testing (the woman and the alleged father(s)).

DNA Sample collection methods

Testing mum

With an AlphaBiolabs prenatal paternity test, there are three options for collection of the mother’s blood sample:

  • The collection can be performed by a nurse or phlebotomist at a local medical practice
  • AlphaBiolabs can arrange for one of its highly trained sample collectors to take the sample from any convenient location (your home or workplace, for example)
  • You can choose to visit one of AlphaBiolabs’ nationwide Walk-in Centres. Here, both blood and mouth swab samples can be collected at the same time, which could save you money on collection fees

Blood samples are time sensitive and need to be returned to AlphaBiolabs’ testing laboratory as soon as possible after being collected.

This is to avoid degradation of the sample which can render a blood sample unusable. For this reason, the use of a trained sample collector is highly advised.

Testing the alleged father(s)

As in a standard DNA paternity test, the alleged father or alleged fathers’ sample(s) involve a mouth swab to collect DNA.

The mouth swab simply needs to be rubbed firmly on the inside of both cheeks for at least 20 seconds to collect cheek (buccal) cells. The man’s sample does not need to be collected at the same location as the mother’s blood sample; a sample collector can visit any convenient location.

However, the samples should be collected around the same time to avoid any delays to the results.

In both instances (testing the mother and alleged father), you can choose to visit one of our Walk-in Centres where our team will be able to perform the collection for you.


How do we know if the man is the biological father of the baby from a prenatal paternity test?

Once both the mother and alleged father’s samples have been received, the samples are sent to AlphaBiolabs’ laboratory where DNA is extracted from both parents’ samples.

DNA from the alleged father’s sample is extracted from the cheek cells collected via the mouth swabs. The isolated DNA samples are then amplified, and state-of-the-art equipment is used to carry out Massively Parallel Sequencing (MPS) – also known as Next Generation Sequencing (NGS) – to analyse up to 153 DNA markers.

By comparing DNA markers in the baby’s DNA profile with the alleged father’s profile, it is possible to identify DNA that has been inherited from the biological father of the child.

If the man tested is indeed the biological father of the baby, both will share DNA in common. When the tested man is not the biological father there will be differences between the DNA of the man and the baby.


How much does a prenatal paternity test cost?

AlphaBiolabs’ prenatal DNA paternity testing starts at £795 with results in four to five days.

For an additional £200 (£995) we can provide results in three days.

You can also spread the cost of the test with interest-free credit if needed.


How conclusive are the results of the test?

We can provide a 99.99% probability of paternity where the father is confirmed as the biological father.

In an extremely small number of cases, the mother’s blood sample may contain insufficient cell-free DNA (cfDNA) from the foetus, which can lead to an inconclusive result.

As a trusted and accredited UK laboratory, it is important for us to make you aware of this potential but very rare outcome.


How accurate are prenatal DNA paternity tests?

Our prenatal paternity test results are 100% accurate based on the samples we receive.


Can I do a prenatal paternity test at home?

Yes, you can. For a prenatal DNA test to be performed at home, we can arrange for one of our specially trained sample collectors to visit your house at an agreed time.

This ensures that your samples are collected correctly (cheek swabs and blood sample for mum) and safely returned to our laboratory for testing.

Alternatively, we can send you a testing kit and you can arrange your own collections through your GP or another medical professional such as a trained nurse of phlebotomist.


Is a prenatal paternity test right for me?

A prenatal paternity test can provide peace of mind in circumstances where you are unsure of who is the biological father of your baby.

We know the sensitivities involved with a prenatal paternity test which is why your test is performed in complete confidence. For confidential advice or to find out whether a prenatal paternity test is right for you, call our friendly Customer Services team on 0333 600 1300 or email


Types of prenatal paternity test

At AlphaBiolabs, we offer non-invasive prenatal paternity testing only, using cheek (buccal) swabs from both the mother and alleged father, and a blood sample from the mother.

However, there are other options available for people seeking a prenatal paternity test.

These include a chorionic villus sampling (CVS) test or an amniocentesis test.


What is a CVS (chorionic villus sampling) test and how is it performed?

For a CVS test, a small sample of cells is taken from the placenta and tested against cheek swabs from both the mother and the alleged father.

The cells are obtained from the placenta by guiding a thin tube through the cervix or using a needle inserted into the uterus to remove a sample of chorionic villus cells.

The test can be taken from as early as 10 weeks into pregnancy. However, unlike a non-invasive test, it is not without risk.

In fact, a CVS test poses a 1% risk of miscarriage. In about 5% of patients, a CVS test is not possible, meaning a non-invasive test – such as that offered at AlphaBiolabs – or an amniocentesis test would be required.


What is an amniocentesis test and how is it performed?

An amniocentesis test can be done between 14 and 20 weeks of pregnancy and is more commonly used to detect chromosome abnormalities or genetic disorders in the unborn foetus.

For an amniocentesis paternity test, your doctor will use a long, thin needle, which is inserted into the abdomen to extract a sample of amniotic fluid from the uterus.

This fluid is then used to retrieve foetal DNA, which is compared to the DNA collected from cheek swabs from the mother and alleged father.

As with a CVS test, amniocentesis poses a small risk of miscarriage (0.5%).


Can I get a prenatal paternity test on the NHS?

The simple answer is no, you cannot receive any form of paternity test (standard or prenatal) on the NHS. However, as costs come down, companies like AlphaBiolabs are making DNA paternity testing more affordable.

Before deciding to take a prenatal paternity test, it is a good idea to discuss it with your GP, who may be able to provide guidance on the options available to you.

Counselling can also help you work through your decision to take a test and the potential implications on yourself and your family.

If you choose to undergo a non-invasive prenatal paternity test, you can also arrange for your blood sample collection to be performed by a nurse or phlebotomist at your local medical practice.


What are the main reasons for taking a prenatal paternity test?

For peace of mind prenatal paternity tests, finding out whether the man is the biological father of the child can have a profound impact on families, especially if the man is found not to be the child’s biological father.

In these cases, knowing early as to whether the man is the child’s biological father can help people make important decisions about the pregnancy.

For legal proceedings, knowing the biological father of the child in early pregnancy can help local authorities and social workers to put plans in place to safeguard a child who might be at risk.

It allows local authorities to perform assessments early in the process, as well as providing time to develop a good working relationship with both the mother and father, especially where there are concerns.

In these cases, a legal prenatal DNA test would be required.


How can I get a paternity test done while pregnant?

AlphaBiolabs’ non-invasive prenatal DNA testing provides the most accurate way to determine paternity before birth.

Want to learn more about our Prenatal Paternity Testing? Call 0333 600 1300 or email and a member of our Customer Services team will be in touch.


Where can I buy a prenatal paternity test?

You can order your prenatal paternity test online now or by calling our Customer Services team on 0333 600 1300.

Casey Randall AlphaBiolabs

Casey Randall

Head of Genetics at AlphaBiolabs

Casey joined the AlphaBiolabs team in 2012 and heads up both the DNA and Covid-19 testing teams.

An expert in DNA analysis and a member of the International Society for Forensic Genetics (ISFG), Casey holds an MSc with Distinction in DNA Profiling and a First-Class BSc with Honours in Forensic Science.

Casey is responsible for maintaining the highest quality testing standards, as well as looking for ways to further enhance the service that AlphaBiolabs provides and exploring new and innovative techniques in DNA analysis.

Connect with Casey on LinkedIn


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