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Urinary hyperglycosylated hCG in first trimester screening for chromosomal abnormalities
M J Weinans1, S A Butler, A Mantingh
1Antenatal Diagnosis Unit, Department of Obstetrics and Gynaecology, University Hospital, Groningen, The Netherlands. m.j.n.weinans@og.azg.nl
Prenatal Diagnosis
|December 13, 2000
Summary
Urine Hyperglycosylated human chorionic gonadotrophin (H-hCG) shows promise for first-trimester Down syndrome screening. Elevated H-hCG levels were detected in Down syndrome cases, suggesting its potential as an early pregnancy screening marker.
Area of Science:
- Biochemistry
- Genetics
- Maternal-Fetal Medicine
Background:
- Hyperglycosylated human chorionic gonadotrophin (H-hCG), or Invasive Trophoblast Antigen (ITA), is a distinct hCG variant with complex oligosaccharide chains.
- Urine H-hCG has demonstrated high sensitivity for second-trimester Down syndrome screening.
- Its utility in early pregnancy screening remains to be fully explored.
Purpose of the Study:
- To evaluate the potential of urine H-hCG as a screening marker for Down syndrome in the first trimester of pregnancy.
- To assess H-hCG levels in pregnancies with trisomy 13 and trisomy 18 during early gestation.
Main Methods:
- Maternal urine samples were collected between 10 and 11 weeks of gestation.
- Samples from Down syndrome, trisomy 13, trisomy 18, and control pregnancies were tested blindly using a specific H-hCG immunoassay.
- H-hCG values were normalized to creatinine concentration and expressed as multiples of the median (MoM).
Main Results:
- The median H-hCG level in eight Down syndrome cases was 3.6 MoM, with five cases exceeding the 90th centile of controls.
- Pregnancies with trisomy 13 and 18 showed significantly lower H-hCG levels (0.2-0.3 MoM), falling below the 10th centile of unaffected pregnancies.
- These findings suggest a potential for H-hCG to differentiate affected from unaffected pregnancies in the first trimester.
Conclusions:
- Urine H-hCG testing may be a valuable tool for first-trimester Down syndrome screening.
- Further research is warranted to determine the full screening potential of urine H-hCG, potentially in combination with other first-trimester markers like free beta-subunit and PAPP-A.