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First trimester maternal serum free beta human chorionic gonadotrophin and pregnancy associated plasma protein A as predictors of pregnancy complications.
Ong CY, Liao AW, Spencer K, Munim S, Nicolaides KH.
BJOG 2000;107:1265-70. -
Maternal serum inhibin-A and free beta-hCG concentrations in trisomy 21 pregnancies at 10-14 weeks of gestation.
Noble PL, Wallace EM, Snijders RJ, Groome NP, Nicolaides KH.
BJOG 1997;104:367-71.