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Prenatal
First Trimester Options
| Question | Answer |
|---|---|
| Between | 11 weeks and 13 weeks 6 days |
| Biochemical alone | 9 weeks and 13 weeks 6 days |
| Components of first trimester risk estimate | 1. Age 2. NT 3. Biochemical Markers |
| First trimester ultrasound evaluation | 1. Heart beat 2. NT 3. GA by CRL |
| Increased NT with normal karyotype | Genetic Syndromes DiGeorge 22q deletion Noonan syndrome Smith-Lemli-Opitz Jarcho-Levine syndrome Beckwith syndrome Fryns syndrome Zellweger syndrome Trigonocephaly C Spinal muscular atrophy GM1-gangliodidosis |
| More increased NT with normal karyotype | Skeletal Dysplasias Thanotophoric dysplasia Achondrogenesis Asphyxiating thoracic dystrophy Campomelic dysplasia Nance-Sweeney Robert syndrome VACTERL association |
| PAPP-A | Secreted by the placenta Detectable at 8 weeks Rises throughout pregnancy Decreased in Down syndrome pregnancies from 8-13 weeks (median MoM 0.40) |
| hCG in the first trimester | Rises rapidly until about 10 weeks gestation After ~10 weeks, declines to approximately 25% of maximal levels by 20 weeks Elevated in Down syndrome pregnancy |
| CVS | Higher rate of complications depending on the facility Placental tissue allows for more ambiguous results from rare confined placental mosaicism Availability of CVS practitioners |
| Integrated test | Combines first and second trimesters 6-7 protein markers total Withholds info |