It is important to the health of any pregnancy that the mum-to-be attends all antenatal appointments and fully understands all the tests recommended to her, even if she decides not to have them. You do not have to have any test or examination you don’t want to when you are pregnant, but tests are usually recommended because there is a real risk to you and/or your baby, and early identification can result in more appropriate and informed decisions, as well as a smoother labour and birth. The number of antenatal tests you are offered in pregnancy depends on whether you are being cared for privately or through a public health service like the NHS, whether there are certain things you are at risk of because of your medical profile or history, and where you are in the world. It is very important to be completely transparent about your current health and medical history, as well as those of your family, your partner, and your partner's family, so your healthcare team can get the clearest possible idea of what tests you may need. The following are common prenatal tests, what to expect, and how you can prepare for them.

Booking Appointment Blood and Urine Tests

The booking appointment is your first midwife appointment in the UK and may be called your first prenatal appointment or OBGYN appointment elsewhere. It usually involves a blood test. A urine test may also be taken to check your sugar and protein levels, which in turn help determine if you need to be monitored for gestational diabetes and pre-eclampsia, respectively, later on.

The booking appointment blood test checks for low blood iron. Your iron levels will be checked at least twice more in pregnancy. Your vitamin levels are generally reduced in pregnancy as a result of the demands growing a baby places on your body, and persisting with your prenatal vitamins and a healthy, balanced diet should keep you in good shape. However, some women start pregnancy with an iron deficiency or develop low iron levels or an iron deficiency after conception, and it is important for mum and baby that this be treated with proper supplementation and/or dietary changes.

The booking appointment blood test also checks for:

Your Rhesus D status (if you are Rhesus negative, you may be further checked for antibodies later in the pregnancy)
Antibodies
Your blood type
HIV
Platelets
White blood cells
Red blood cells
Pre-existing rubella immunity
Hepatitis B
Syphilis
Sickle cell disease and thelassaemia (if your background suggests you are at risk)

Part of the reason your healthcare team needs to know so much about your blood is so that a blood transfusion can be given safely to you in an emergency situation. If you have a personal issue with blood transfusions because of your religious beliefs, you need to tell someone looking after you as soon as possible.

Why isn’t there a routine screening for vitamin D and other vitamin deficiencies in pregnancy?

There isn’t enough evidence to suggest that screening on a national level for specific vitamin deficiencies is necessary, and it can be expensive. Vitamin D supplementation may be routinely recommended to pregnant women in countries where the climate makes deficiency common. You are right to worry about deficiencies affecting your own health and that of your baby. Ask your doctor about any deficiencies that concern you rather than beginning a course of anything independently, even if it is over-the-counter and/or you’ve taken it safely before. You should always check with an appropriate healthcare professional before taking anything while you’re pregnant.

Down’s Syndrome, Edwards’ Syndrome, and Patau Syndrome Combined Tests (Blood Tests and Ultrasound Scans) and Amniocentisis or Chorionis Villus Sampling (CVS).

Downs’, Edwards', and Patau are genetic syndromes that happen at the moment of conception; your baby doesn’t develop them in the womb, and the mother doesn't do anything to cause them. The combined tests, which involve a blood test and an ultrasound scan, allow affected parents to make informed decisions. The combined tests are options offered by the NHS and other health services, usually between 10 and 14 weeks of pregnancy. They are very safe and do not carry a risk of miscarriage.

The combined tests are risk assessments; they will only tell you about your baby’s risk of having one of these conditions; they won’t tell you whether your baby has one. For this, you will be offered an amniocentisis test or chorionis villus sampling once it’s been established your baby is at high risk. These tests are invasive (usually involving a needle through the mother’s abdomen, though CVS sampling can also be conducted trans-vaginally) and carry a small risk of miscarriage.

A Down’s Syndrome pregnancy is considered high risk and will result in lots more prenatal appointments and monitoring for mum, as well as extra information to take in before the baby arrives. Edwards’ and Patau have a high risk of miscarriage, so can also lead to changes in your pregnancy care if they are discovered. Most babies with them will die before or shortly after birth. Tragically, it is rare that a baby with Edwards’ or Patau syndrome survives until adulthood.

Oral Glucose Tolerance Test

At your first prenatal appointment, you will be asked a series of questions to determine your risk of gestational diabetes. The oral glucose tolerance test (OGTT) will be offered to some pregnant women between 24 and 28 weeks of pregnancy. If you have one or more risk factors for gestational diabetes, you should be offered this screening test. Risk factors may include your age, weight, medical history, family medical history, and ethnicity. It is essential to have this test done because gestational diabetes comes with significant health risks for you and your baby and could complicate your labour and delivery. The OGTT may be done earlier if you have a high glucose level in your urine during your first midwife appointment, if you've had gestational diabetes in a previous pregnancy, or if you have a high risk for diabetes.

You will be asked to fast for eight to ten hours prior to the appointment, though you're usually allowed to have water. The test is performed by a doctor or midwife. You will have a blood test that morning and then be given a very sugary glucose drink and told to rest for two hours. Then another blood sample is taken to check how you've metabolised the glucose. You get the results back pretty quickly, usually within 24 hours, and, from there, your doctor will be able to diagnose gestational diabetes or your blood glucose level as normal.

Genetic Testing in Pregnancy

You can opt to have private genetic testing while you are pregnant if you are concerned about certain genetic conditions beyond what we’ve covered above. While these tests can be controversial—potentially causing stress, relationship discord, and increasing ableist stigma around certain disabilities—some parents consider them worth doing so that they can make informed decisions about the fetus’s future. However, beyond the Down’s, Edwards', and Patau Syndrome tests mentioned above, genetic tests are not typically offered as standard tests by the NHS unless your baby is at high risk of developing them (for example, if both parents have family histories of cystic fibrosis). Genetic testing is generally considered to be safe and can be both noninvasive and invasive. Any invasive testing carries a small risk of miscarriage. The accuracy of these tests can vary. Please ask your obstetrician and test provider about any private genetic testing preparation.

Mental and Emotional Health Preparation for Tests

Every pregnancy and parent is different, and any tests can be stressful and anxiety-inducing, whether your history with them is negative or not. Letting your healthcare team know about these feelings from your first interactions with them is an important part of advocating for yourself and your baby in pregnancy. There are steps they can take to make testing easier for you, even if it is just treating you in a more compassionate way or repeating things when you’re calm enough to understand them. Your mental state and stress levels are known to impact your growing little one, and you cannot adequately take care of them if you don’t get the best possible care for yourself.

For more information on caring for yourself in pregnancy, please check out Unii’s expert-led Antenatal Course, coming soon to Unii.com.

Antenatal (Prenatal) Tests: What to Expect