Study of serum SP1 levels in early normal and abnormal pregnancies

The pregnancy-specific beta 1 glycoprotein (SP1) levels in the serum of normal and abnormal pregnancies were determined by radioimmunoassay in the first trimester. The results indicated that serum SP1 levels of normal pregnancies increased with the advancing gestational week; 67% of threatened abortions with low SP1 levels would finally abort and only 7% of those with normal SP1 levels would abort. Serum SP1 levels were of lower values in ectopic pregnancy and hydatidiform mole. Serum SP1 might be taken as a better index for estimating the fetal prognosis in threatened abortion and an auxiliary diagnostic means for ectopic pregnancy and hydatidiform mole.