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CHANGES TO THE SCREENING GUIDELINE:
1. New eligibility criteria for NT ultrasound (as part of IPS):
As of January 2010, the following women qualify for NT ultrasound to be done in conjunction with first and second trimester serum markers (IPS):
a) Women >36 years old at expected date of delivery (EDD);
b) Women with twin pregnancies;
c) Women who have a history of a previous child or fetus with Down syndrome, trisomy 18 or trisomy 13;
d) Women >35 years old with 3 or more miscarriages;
e) Women who are HIV positive; and
f ) Women pregnant following in vitro fertilization and intracytoplasmic sperm injection.
2. Screening in twin pregnancies:
Based on published studies, screening twin pregnancies with both NT ultrasound and serum markers reduces the false positive rate while maintaining a high detection rate as compared to NT ultrasound alone.
As of January 2010, women pregnant with twins should be screened by NT ultrasound and first and second trimester serum markers (IPS). If NT is not available, SIPS should be offered. If the patient presents after 13 weeks 6 days gestation, Quad should be offered. Women who are >35 years old have the option of amniocentesis without prior screening.
Screening in higher multiples will remain based on NT alone. | 
