What tests are taken during pregnancy

At your first antenatal appointment, known as the booking appointment, your midwife will explain about the different tests and checks on offer, including the reasons they give them. This will include ultrasound scans and other screening and diagnostic tests to check your baby’s development.

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Routine tests in pregnancy
Blood pressure checks
Urine tests
Blood tests
Measuring your baby’s growth
Abdominal palpation (feeling your womb)
Other tests available (Group B Strep)

The same tests are offered to all pregnant women and it's your decision whether you have them.

Everything the midwife offers is there to help you and your baby but you have the right to refuse any tests that you are offered. If anything worries you about any of the tests, talk to your midwife.

Routine tests in pregnancy

These tests are done at your antenatal appointments to check your health and help spot certain issues that might crop up in pregnancy.

Blood pressure checks

Blood pressure is measured using a cuff that is wrapped around your upper arm. It's a good idea to wear a short-sleeved top for this. The reading from your first blood pressure check will give the antenatal team a starting point. From that reading they can see whether later readings are too high or too low for you. Blood pressure checks should ideally be done on the same arm every time.

Blood pressure is checked because raised blood pressure can be a warning sign of pre-eclampsia, a pregnancy condition that can be serious.

Urine tests

You will be asked to give a sample of your urine at your booking appointment to check for proteins and screen for any infections. Your urine is checked during antenatal checks for certain conditions that can be caused by pregnancy, such as pre-eclampsia and gestational diabetes. If you show any symptoms of having a urinary tract infection (UTI) at any time during your pregnancy, you will also be asked to give a urine sample.

The midwife, nurse or receptionist will give you a little pot to take into the toilet for this. It’s important to give a sample that is ‘midstream’ – this means it is taken halfway through weeing.

Blood tests

During pregnancy, your blood is tested for different things. Your midwife or doctor should explain this and tell you why the blood tests are being offered to you. They should also explain that it’s your choice whether you have the tests or not.

If you agree, the midwife will take a blood sample. If you are worried about the test, or afraid of needles, talk to your midwife about your concerns. These blood tests are usually taken only twice in pregnancy – you might have more if you need to be watched more closely for a specific reason. Your midwife or other medical professional will always talk to you first if you need more tests and will only take the blood test with your permission.

The first blood test will be offered in early pregnancy. This will look at:

your blood group and rhesus status
whether you have infections such as hepatitis B, HIV or syphilis
anaemia (not enough iron in the blood)
whether you are immune to German measles (rubella), a disease that can affect unborn babies
whether you have blood conditions such as sickle cell anaemia or thalassaemia.

Later on in your pregnancy, around 28 weeks, you may be offered another blood test to check your iron levels again. In some cases, this test will also check whether you have developed pregnancy diabetes.

Measuring your baby’s growth

From 24 weeks your midwife will start to measure your growing bump to check that your baby is growing well. This is a simple test using a tape measure. She will measure your bump, in centimetres, from your bikini line to the top of the uterus. This will be plotted on a graph in your notes. The measurement should be the same as the number of weeks you are, give or take 1–2 cm.

Abdominal palpation (feeling your womb)

The midwife will feel your womb to check which position your baby is in. This will usually be performed at 36 weeks or earlier. This tells the midwife if the baby is in the right position for birth. They will usually listen to your baby’s heartbeat as well.

Other tests available (Group B Strep)

Group B Strep is a type of bacteria called streptococcal bacteria, which lives in the body. It is common (around 20% of women in the UK have it) and doesn’t usually cause any health problems.

The GBS bacteria do not produce any symptoms in women during pregnancy and your baby will usually be born healthy. However, there's a small risk it could spread to your baby during labour and make them ill. There’s also an extremely small risk you could miscarry or lose your baby.

Group B Strep not routinely tested for but may be found during tests carried out for another reason, such as a urine test or vaginal swab.

If you're worried about group B strep, speak to your midwife or GP for advice. Routine testing isn't currently recommended and tests are rarely done on the NHS, but you can pay for one privately.

Find out more about Group B Strep in pregnancy.

Routine tests help keep close tabs on you and your baby. That’s why it’s so important to keep all your prenatal appointments. Screening tests can spot potential problems early.

These tests usually include:

History and physical exam. During your first or second prenatal visit, you’ll answer a lot of questions about your health and family history. This information helps the doctor know whether you have any specific risks to address, such as an inherited genetic disorder. You will also have a physical exam. Your doctor will calculate your due date based on the date of your last menstrual period.

Pelvic exam and Pap smear.Prenatal testing during the first trimester begins with a pelvic exam and Pap smear to check the health of your cervical cells. This testing screens for cervical cancer and for certain sexually transmitted diseases (STDs).

Blood tests. During one of your first visits, your doctor or midwife will identify your blood type and Rh (rhesus) factor, screen for anemia, check for immunity to rubella (German measles), and test for hepatitis B, syphilis, and HIV and other STDs.

Depending on racial, ethnic, or family background, you may be offered tests and genetic counseling to assess risks for diseases such as Tay-Sachs, cystic fibrosis, and sickle cell anemia (if these weren't done at a preconception visit). Testing for some of these diseases can also be done with saliva.

You might be tested for exposure to diseases such as toxoplasmosis and varicella (the virus that causes chickenpox. Your health care provider may also want to check your levels of hCG, a hormone secreted by the placenta, and progesterone, a hormone that helps maintain the pregnancy.

Urine tests. You will also be asked early on for a urine sample so that your doctor or midwife can look for signs of kidney infection and, if necessary, can confirm your pregnancy by measuring the hCG level. (A blood hCG test to confirm pregnancy may be used instead.) Urine samples will be collected regularly to spot glucose (a sign of diabetes) and protein, which could show preeclampsia, a pregnancy-induced disease marked by high blood pressure.

In the later part of the first trimester you will be offered genetic testing. Some people feel like these tests may cause them undue stress, and they prefer to make sure the baby is genetically normal after delivery. Others want all the testing they can get, realizing that these tests sometimes are not 100% accurate. Talk with your doctor or with a genetic counselor about the pros and the cons before you decide. There are different genetic testing options that involve blood tests alone or with an ultrasound that involve no risk to the fetus. If these noninvasive tests are abnormal, you might have further tests.

One first semester genetic test combines a blood test with an ultrasound to screen for Down syndrome. It may be available between 11 and 14 weeks of pregnancy. The results of a blood test that measures hCG and PAPP-A (pregnancy-associated plasma protein A) in maternal blood are used with an ultrasound measurement of the skin at the back of the fetus’ neck (called nuchal translucency). The procedure may be able to spot many Down syndrome cases and other genetic conditions. However, as with all screening methods, a more invasive diagnostic technique like CVS is used if results are positive.

Noninvasive prenatal testing (NIPT). This cell-free fetal DNA test can be done as early as after 10 weeks of pregnancy. The test uses a blood sample to measure the relative amount of free fetal DNA in a mother's blood. It's thought that the test can detect 99% of all Down syndrome pregnancies. It also tests for some other chromosomal abnormalities.

Chorionic villus sampling (CVS). If you're 35 or older, have a family history of certain diseases, or have had a positive result on noninvasive genetic tests, you will be offered this invasive test, usually between 10 and 12 weeks of pregnancy. CVS can detect many genetic defects, such as Down syndrome, sickle cell anemia, cystic fibrosis, hemophilia, and muscular dystrophy. The procedure involves threading a tiny catheter through your cervix or inserting a needle into your abdomen to get a tissue sample from the placenta. The procedure carries a 1% risk of inducing miscarriage and is about 98% accurate in ruling out certain chromosomal birth defects. But, in contrast to amniocentesis, it does not help in detecting neural tube disorders, such as spina bifida and anencephaly, or abdominal wall defects.

Be sure to discuss all of your testing options with your doctor so that together you can decide on the ones that will be best for you.

If you’re expecting twins, it’s a high-risk pregnancy. For this reason, your doctor will want to watch you and your babies closely. You'll have all the routine tests, but expect to have some of them earlier and more often.

Your doctor may suggest that you see a perinatologist, also called a maternal fetal medicine specialist. These doctors are obstetricians who specialize in high-risk pregnancies. They may work with your regular obstetrician to manage your pregnancy and order tests.