Past generations didn’t know how a baby was doing practically until it was born. Technical resources were much more limited than they are nowadays, as well as the understanding of the origin of some problems during pregnancy.  Technological advances in the last decades have also reached the OB/Gyn field, and nowadays they offer a series of routine tests to check the status of the baby that is on the way.

Every test must usually be done at a certain time and some are only carried out if a particular problem is observed. In general, prenatal tests may be divided into three different groups.  

Imaging tests

The ultrasound or sonogram has become an indispensable tool to monitor the baby, since its introduction 40 years ago. Since then, no problems have been documented because of its usage.  Ultrasounds work in a similar way as radars do: images are obtained by means of the sound waves emitted by a gadget they will rub over your belly, or introduce in your vagina. Then the technician or the doctor will interpret those images to see if everything is ok. The ultrasound can determine whether there is a heartbeat, where the placenta is, or if there are visible malformations.

There are different types of ultrasounds, but they are all based on the same system for obtaining images by means of sound waves.

Screening tests

These tests provide information on the baby’s well-being, but they are not definitive data because all they give is a probability: the probability rate that your baby has of having a genetic defect or any other kind of anomaly.  

Screening tests can often provide what is known as a “false positive” result. They initially indicate there could be a problem, but when the tests are repeated, or other more conclusive tests are done, it turns out that there was no such problem. For that reason, if you get a “false positive” result, try not to fret until you get the results of the final tests.

Screening or probability tests are usually carried out by means of a blood test, or a blood test in combination with imaging tests, such as an ultrasound.  

Genetic tests

These tests, contrary to screening tests, do offer a definite and final result. Genetic testing takes a sample of the baby’s genetic material in order to analyze it and establish whether there is an anomaly in the baby’s chromosomes. This genetic material may be obtained in different ways, depending on your phase of pregnancy.  

Within genetic testing, the most widely known is amniocentesis, that is carried out between weeks 15 and 18 of pregnancy. However, there are other tests that may be done even before that.  

Some of these tests are offered routinely, because of the mother’s age or in the event that she may be at risk because of her personal medical history of having had a baby with a chromosomal alteration. Other times, these tests are carried out in order to confirm or rule out a positive screening test.

In either case, remember that carrying out these genetic tests is a recommended by your doctor, but you can always opt out of them. It is important that you are aware of the information you will get from each test, and that you consider whether it is worth running the small risk of miscarriage they entail if the information you get is going to dispel your fears.  

Always share your doubts with your doctor, and comment with her all the information that could help determine whether it is advisable for you to undergo genetic testing or not (for example, if there is a hereditary genetic illness in your family).

If you still have doubts or concerns after speaking with your doctor, you can always request an appointment with a genetics counselor. Your doctor’s office may offer those services. If not, ask your doctor for a referral.