URINARY β-CORE hCG: SCREENING FOR ANEUPLOIDIES IN EARLY PREGNANCY (11-14 WEEKS' GESTATION)

Initial studies at 17–22 weeks' gestation evaluating urinary β‐core human chorionic gonadotrophin (hCG) as a marker for Down's syndrome had suggested that it may have more potential than its serum counterpart. This study measured maternal urinary β‐core‐hCG and creatinine at 11–14 weeks' gestation in a series of 26 aneuploidies (nine trisomy 21, five trisomy 18, four 45,X0, and eight others). The normal range for β‐core‐hCG and β‐core‐hCG/creatinine was derived from 198 normal singleton pregnancies. Trisomy 18 cases (n=5) had low maternal urinary β‐core‐hCG creatinine levels (median 0·35 MOM, range 0·08–0·82 MOM), whereas the other aneuploidies had no particular pattern; in particular, the trisomy 21 cases (n=9) (median 1·16 MOM, range 0·3–4·74 MOM) did not differ significantly from 1 MOM. The findings imply that maternal urinary β‐core‐hCG is not as discriminating for Down's syndrome between 11 and 14 weeks as later on in pregnancy. © 1997 John Wiley & Sons, Ltd.