08
Nov
In vitro diagnostic testing can aid in diagnosing "high risk" pregnancies
Although prenatal testing is optional for any pregnant woman, there are instances when it’s important for the upcoming newborn.
Diagnostic testing, one of the two categories of prenatal testing along with screening tests, was developed for pregnancies at “high risk” for a chromosome abnormality. Diagnostic testing can determine whether the fetus is affected or not. Women considered at “high risk” to have a baby with a chromosome problem include women who will be 35 years old or older at the time of delivery or women who have had an abnormal screening test.
Dr. Scott MacGregor, MD, selected as a Chicago Top Doctor by TopTierMD as a top rated obstetrician in Chicago and considered one of the leading specialists in the field of prenatal testing, is the Director of the Division of Maternal-Fetal Medicine and leads a team of eight specialists at The Centers for Maternal and Fetal Health of Evanston Northwestern Healthcare.
“We were one of first centers in Chicago to be involved in first trimester genetic screening,” Dr. MacGregor said. “We were involved in the initial study to evaluate the use of this and were one of the early leaders in this field.”
Diagnostic testing combines a maternal blood screening test with an ultrasound evaluation of the fetus to identify risk for specific chromosomal abnormalities, including Down’s Syndrome Trisomy-21 and Trisomy-18.
Dr. MacGregor said that in addition to screening for these abnormalities, a portion of the test, known as the nuchal translucency, can assist in identifying other significant fetal abnormalities, including cardiac disorders.
The First Trimester Screen is performed between the 11th and 13th week of pregnancy. Because the test is performed so early, it is often used to determine whether a mother should consider undergoing an early - first trimester - diagnostic test, such as chorionic villus sampling or second trimester amniocentesis.
A study published in the New England Journal of Medicine in November 2005 determined that first trimester screening was the most accurate non-invasive screening method available.
The screening primarily looks at the neck thickness of the baby, plus markers in the blood. Except for the discomfort of drawing blood, there are no known risks or side effects associated with First Trimester screen.
Dr. MacGregor's team does nearly 30,000 First Trimester screenings a year and MacGregor believes that there’s no way a consumer can get the same level of experience from a doctor’s office.
“What people may not know is we do thousands of these a year so we should, and do, do them better, and I think this is really is where they can get highest quality service,” Dr. MacGregor said. “In addition, if there are abnormalities when someone is having this done at another place, they end up being sent to us anyway.”
The Center also offers additional consultative sevice for women whose fetuses are identified as having birth defects or are suspected to require special needs at delivery, including Neonatology, Pediatric Cardiology, Pediatric Surgery and Radiology
“We also use assessment of the nasal bone and it increases the detection of chromosomes abnormalities by about 10 percent, so we can offer screening that most centers in the Chicago area can’t,” Dr. MacGregor says. “We can predict 95 percent. Most others predict about 85 percent.”
Dr. Scott MacGregor, MD, was selected by TopTierMD as a Chicago Top Doctor and is considered one of the best obstetricians in Chicago. He specializes in treatment of complicated pregnancies, genetic screening and in vitro transfusions.
