Detection of hydatidiform mole in maternal serum screening programmes for Down's syndrome.

OBJECTIVE

To determine how frequently hydatidiform mole will be detected in a maternal serum Down's syndrome screening programme.

DESIGN

Affected pregnancies were identified using a national register. Unconjugated oestriol (uE3) and human chorionic gonadotrophin (hCG) were measured in stored serum samples and alphafetoprotein (AFP) levels were available from previous neural tube defect screening at 15-20 weeks gestation.

SUBJECTS: Ten pregnancies with a complete mole (i.e., hydropic placenta without a fetus), nine with stored serum samples and one with an AFP level only.

RESULTS

The median values were 0.08, 0.13 and 1.83 multiples of the normal median for AFP, uE3 and hCG respectively. Six out of nine (67%) tested for all three markers had a high risk of Down's syndrome given maternal age and the marker levels.

CONCLUSION

Many molar pregnancies that have not presented clinically before 15 weeks will be detected through Down's syndrome screening.