Patients
Practioners
General Information
Other UWMC Obstetrical Specialty Care Clinics
Fetal Therapy Program
Department of Obstetrics & Gynecology
University of Washington School of Medicine
(206) 598-8130 (206) 598-2359 fax
Maternal screening is evolving and there are many more options now available to your patients than in the past. The purpose of this fact sheet is to outline the options so that you can help your patients decide if/how they wish to proceed with screening.
What is the purpose of screening?
All couples have a 3-5% risk to have a baby with a birth defect. The purpose of this screening process is to try to identify those low risk individuals who have a significantly increased risk for certain defects, Down syndrome, Trisomy 18 or Neural tube defects, and therefore should be offered more invasive forms of prenatal diagnosis.
Screening at the University of Washington
At The University of Washington Medical center we provide a Prenatal Genetic Risk assessment package integrating, family history, ethnic background, pregnancy history, maternal and paternal age, first and/or second trimester ultrasound findings and serum screening (1st and/or 2nd trimester serum screen).
A genetic counselor can assess the patients risk and discuss the implications with her. This assessment is available to all pregnant women to help the patient make informed choices about their options during a pregnancy.
Screening Options
|
First Trimester |
Second Trimester |
||||
|
Serum only |
Nuchal only |
Serum & Nuchal |
Quad Serum only |
NT & Quad serum |
NT & Combined Serum (integrated) |
Gest. Age |
10 3/7–12 6/7 |
11–13 6/7 |
10 3/7–13 6/7 11–12 6/7 |
15–20 |
|
|
Detection Rate |
75% (tri 21) 90% (tri 18) |
70% (tri 21) |
85% (tri 21) 97% (tri 18) 50% (heart defects) |
70% (tr 21) 90% (tri 18) |
80% |
85% |
FP |
5% |
5% |
5% |
5% |
1.4% |
1.0% |
Proteins |
PAPP-A Free-Beta HCG |
|
|
AFP Estriol |
HCG Inhibin A |
|
Pattern in DS |
|
|
|
|
|
|
Advantages |
Earlier Results |
|
Higher detection than serum alone |
|
|
Highest detection rate Lowest false positive rate |
Disadvantages |
Will not screen for NTD's Lower detedtion rate Small window of opportunity |
Higher false positive than combined Small window of opportunity |
Must be done in specialized center by certified sonographer |
Later results |
|
Wait till 2nd trimester to get results |
*Suruss study 2003
These results do not factor in second trimester ultrasound markers. A Normal 2nd trimester fetal anatomy scan at 18–20 weeks in a tertiary center can further reduce the risk by 0.4 fold.
Last Updated:
4/12/07