To put it simply, prenatal genetic screening is a process that is designed to discover whether or not a fetus has certain disorders relating to their genes. It is a service that is offered by private health clinics as well as many of the larger hospitals in the country. Genetic screening before birth is not for everyone but it certainly has its advocates, especially when there is a known genetic defect in the parentage of the individuals concerned. When prenatal screening takes place, there is no onus on the parents to make any decisions — it simply informs them of any potential genetic disorders they may have to face when the baby comes to term.
What Is a Genetic Disorder?
Genetic screening services look for multiple disorders. In some cases, there may be extra or missing chromosomes in the fetus. This is known as aneuploidy. There again, there may be an inherited disorder that one — or both — parents has passed onto their offspring. This is known as a genetic mutation. There are many such disorders to screen for. Two examples that are reasonably common in the Western world are cystic fibrosis and Huntington's disease. Although they affect people differently, there are common traits some of which can be life-threatening or limiting depending on the disorder.
Is Prenatal Genetic Screening the Same as Diagnostic Testing?
No, they are not the same. Genetic screening means checking for a range of potential disorders. What medics will be able to offer following a screening test is the likelihood of a particular condition. Usually, this is presented in the form of a percentage to give an indication — never complete assurance — of either the absence or presence of such a condition. On the other hand, a prenatal diagnostic test looks for a specific disorder. In some cases, cells are taken from the placenta, or the fetus itself, so that a sample test can be conducted. Therefore, genetic screening tests usually come before any diagnostic testing.
What Is Needed for Prenatal Genetic Screening?
Parents-to-be can have their blood taken and be tested for any potential genetic mutations they might pass on. It is a useful procedure for couples who are planning to start a family and want to understand exactly where they stand, especially if one or other of them has a known disorder themselves. That said, any couple can be screened. If a screening service is offered after conception, then ultrasound techniques and samples of the mother's blood tend to be used.
