SERPINB5 and trisomy 18: The risk of trisomy 18 was significantly increased in women with U-maspin or M-maspin concentration greater than the cutoff values compared with women whose values were lower than the cutoff values [OR 265.0 (95% CI: 21.9–3208.3, P<0.001) for U-maspin concentration; OR 29.3 (95% CI: 3.4–249.7, P<0.001) for M-maspin concentration].