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The usefulness of hCG and unconjugated oestriol in prenatal diagnosis of trisomy 18

1996; Wiley; Volume: 103; Issue: 4 Linguagem: Inglês

10.1111/j.1471-0528.1996.tb09738.x

1471-0528

Nathalie Leporrier, Michel Herrou, M. Herlicoviez, Pierre Leymarie,

Tumors and Oncological Cases

Objective To evaluate the usefulness of the two maternal serum markers, human chorionic gonadotrophin (hCG) and unconjugated oestriol (uE 3 ), in the prenatal diagnosis of trisomy 18. Design Retrospective evaluation of uE, and hCG levels at mid‐trimester in cases of trisomy 18 pregnancies identified from a series of women screened for Down's syndrome. Setting From a series of 53,893 women screened in the antenatal centre of University Hospital of Caen (France), 22 cases of trisomy 18 were diagnosed either after amniocentesis for maternal age, elevated risk of Down's syndrome, or fetal abnormalities and/or growth retardation on ultrasound assessment, or after birth. In addition, 11 cases of trisomy 18 identified prenatally in two other centres were included. Results Individual hCG and uE 3 levels for pregnancies with trisomy 18 were significantly lower than in unaffected pregnancies: mean hCG was 0.62 multiples of the median (MOM) and median hCG was 0.5 MOM. uE 3 was a much more effective marker than hCG. Mean uE 3 was 0.40 MOM and median uE 3 was 0.37 MOM. It was observed that screening for trisomy 18 based on selection for amniocentesis with cut‐off values of 035 for hCG and 0.60 for uE 3 would lead to a detection rate of 48 % for 0–8 % false positive rate. Using cut‐off values of 0.70 MOM for each one of the two markers would detect 79YO of cases of trisomy 18 with a 3% false positive rate. Conclusions Our results confirm that low hCG and uE 3 levels observed in the mid‐trimester are predictive of an increased risk for trisomy 18. Since most fetuses with trisomy 18 exhibit morphological abnormalities which should be detected following a careful ultrasonographic examination, biochemical screening could help in the detection of those anatomical defects in selecting for scanning a group of high risk women.