Physicians perform amniocentesis or chorionic villus sampling (CVS) as diagnostic procedures. The test administered varies according on the stage of pregnancy: Amniocentesis is carried out after 15 weeks, and CVS is carried out between 10 and 13 weeks.

The choice between the two tests usually depends on the timing of a patient's abnormal screening test results or when they would like to have diagnostic testing done."There are small differences in what the two tests can find," she added.

Amniocentesis and CVS both examine cells taken straight from the fetus. Amniocentesis samples the amniotic fluid, which contains fetal cells, while CVS samples the placenta.

Who Receives Diagnostic Testing During Pregnancy?

Not all patients who receive aberrant findings from a blood test or ultrasound are referred for diagnostic testing. Additionally, people who have a family history of a certain genetic disorder can benefit. Individuals who are 35 years of age or older who are expecting a child may consider getting tested for Down syndrome. Regardless of age or other risk factors, the American College of Obstetrics and Gynecology advises that diagnostic testing be made available to all pregnant women.

Genetic counselors can assist you in determining if diagnostic testing is necessary.

Based on family history, they may be involved early in the pregnancy. Genetic counselors will be consulted if any anomalies are found during ultrasound screening. They are right there with us, educating patients about the potential effects of their diseases on a pregnancy or a child's future development.

Genetic counselors can also tell patients about a genetic disorder and its potential effects on their unborn child if testing reveals the presence of the problem. Patients can use this information to make educated decisions regarding their prenatal care.

What Happens During Diagnostic Testing?

For diagnostic testing, OB-GYNs may refer patients to specialists in maternal-fetal medicine. Both amniocentesis and CVS are done on conscious patients in medical offices. Every test involves the physician taking a sample of cells with a fine needle, which are then analyzed for anomalies.

Both procedures use ultrasound guidance, allowing us to see where we placed the needle, according to Seet. Transcervical or through the cervix is the usual route for CVS. Amniocentesis is performed via the abdominal cavity.

The chance of transient bleeding, cramps, or infection is increased with both tests. The majority of people don't have significant adverse effects, however miscarriage is around 1 in 500 times more likely.

What to Expect After Diagnostic Testing

Following CVS or amniocentesis, patients are advised to rest and refrain from strenuous lifting.

They ought should be able to resume their regular activities in a few days.

The sampled cells are examined in a lab to check for chromosomal abnormalities or gene alterations. Genetic disorders such as Tay-Sachs disease, cystic fibrosis, and Down syndrome can result from any variant of these. Patients usually obtain their test results in a span of two to three weeks.

The fetus does not have the suspected illness if the test findings are normal. Maternal-fetal medicine professionals may do an ultrasound to further evaluate the issue if diagnostic testing indicates that a developing baby has a syndrome or ailment. Pregnant patients and their partners will discuss the test results with genetic counselors and physicians who specialize in maternal-fetal care.