Drs. Heather Scott and Jo-Ann Brock - Obstetrics & Gynecology
Prenatal screening: Researchers look for more telling signs of risk or reassurance
Obstetrician Dr. Heather Scott wants to know which pregnancies should be stringently monitored, and which ones can safely be allowed to progress under typical prenatal care.
She is investigating how results of prenatal screening tests—such as maternal serum testing and fetal ultrasound scans—may be interpreted to shed light on which pregnancies are, and are not, at risk of adverse outcomes.
Heather is working with Dr. Jo-Ann Brock—a colleague in the Division of Maternal-Fetal Medicine—to see if fetal growth characteristics that show up in the 18- to 20-week ultrasound can help predict whether or not a fetus is at risk. They are examining more than 1,500 pregnancies in which women had unexplained positive maternal serum results, and comparing the ultrasound findings with data about how the pregnancy proceeded and how the fetus fared.
“While maternal serum testing is done to calculate the chances that a fetus will have spina bifida or a chromosomal abnormality, a positive test result does not necessarily mean a fetus will be born with one of these problems,” Heather says. “It is only an indicator of risk. However, we suspect that a positive result that is not related to spinal or chromosomal abnormalities may actually provide clues to other sorts of risk.”
Heather and Jo-Ann believe an otherwise unexplained positive maternal serum test could indicate a problem with the placenta. For example, there might not be enough blood flow, or it could be separating from the uterine wall. Such problems can impair the growth and development of the fetus, or cause bleeding in the mother, spontaneous pre-term delivery or even fetal death.
They want to know if the 18- to 20-week ultrasound results can provide either reassurance that all is well with placenta and fetus, or a clear indication that the pregnancy needs to be watched more closely, when there’s an unexplained positive serum test result. “If we can confidently determine early on that a fetus is not growing properly, we can monitor that pregnancy very closely,” notes Jo-Ann. “If the fetus continues to show signs that it is not growing well, we can intervene to deliver the baby early.”
Heather is also working with colleagues and trainees to determine how well health professionals who work with pregnant women understand the maternal serum test. “We want to ensure they understand it provides a proxy measure of risk, rather than a definitive diagnosis,” she says. “We also want to look into the way test results are delivered to women and how they respond to them.” Ultimately, she wants to ensure that health providers and women understand the potential implications of positive maternal serum test results, and how other screening test results and clinical indicators may interact with them to predict risk.
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