Ultrasound
I Trimester
- Confirmation of pregnancy / viability scan
- Nuchal translucency scan / early anomaly scan.
- Done at 11 – 14 weeks [CRL – 45 – 84 mm] as a part of aneuploidy screening. Helps to pick up major structural abnormalities at the earliest.
II Trimester
Target scan
- Done at 20 – 24 weeks.
- Detailed targeted examination of the fetus to pick up fetal abnormalities.
Fetal echocardiography
- Done at 20 -24 weeks
- Indications
- Previous child with heart disease.
- Mother with heart disease.
- Overt diabetes mellitus.
Fetal Neurosonogram
- Done as extended survey if we detect any central nervous system abnormality during target scan.
III Trimester
- Growth scan with Doppler
Multiple pregnancy
- Specialized unit for scanning multiple pregnancies , counselling the couple and guidance for monitoring higher order pregnancies
Screening Test
- First trimester combined screening tests[NT+ Biochemical screening],
- Done along with nuchal translucency scan at 11 – 14 weeks [ CRL 45 – 84 mm].
- Blood is collected on dried blood spot filter paper and analysed for two markers – PAPP – A and β – HCG.
- Results of the blood part and ultrasound are combined to estimate the risk of down syndrome, trisomy 13 and trisomy 18.
- This is a screening test with a detection rate of 85 – 90 %.
Screen Negative / Low risk
- The baby is at low risk for Trisomy 21(downs syndrome), trisomy 13 or 18.
- Do a target scan at 20 weeks.
Screen Positive / High risk
-
- The baby is at increased risk for Trisomy 21[down syndrome], trisomy 13 or 18
- Since this is a screening test, it should be followed by a confirmatory test like Chorionic villi sampling or Amniocentesis
or
- You can do a test with high sensitivity like Noninvasive prenatal screening [NIPT]]with 99.9 % sensitivity – still this is a screening test and if positive should be followed by a confirmatory test like Amniocentesis / Chorionic villi sampling.
Quadruple screening test
- Quadruple screening test
- This is a maternal blood screening test that looks for AFP,B HCG, Unconjugated estriol and Inhibin-A.
- Done at 16-21weeks,when BPD is 31-52MM.
- This test has a sensitivity of about 60-70% for detection of downs syndrome.
Non invasive prenatal screening test[NIPS]:
- Has a sensitivity of 99% for detection downs syndrome .
- This is also a screening test. If screen positive – this has to be confirmed with Amniocentesis or Chorionic villi sampling.
- Preeclampsia screening test
Fetal Interventions
- Chorionic villi sampling
- Amniocentesis
- Fetal reduction
- Intrauterine transfusion