Pregnancy‐Specific β 1 ‐Glycoprotein (Spo Levels Measured by Nephelometry in Serum from Women with Vaginal Bleeding in the First Half of Pregnancy

. Pregnancy‐specific β 1 ‐glycoprotein (SP 1 ) levels were measured by nephelometry in sera from 107 women admitted to hospital because of vaginal bleeding in weeks 8 to 20 of pregnancy. The SP 1 results were compared with those in single samples from 655 women and serial samples from 9 women with uncomplicated single pregnancies in the same period. The possibility of predicting the outcome of a pregnancy complicated by vaginal bleeding was calculated on the basis of the SP 1 level on admission to hospital. In 65 % a normal SP 1 value predicted continuation of pregnancy, whereas a low SP 1 value invariably predicted spontaneous abortion.