Maternal serum ${eta}$-specific human chorionic gonadotropin(${eta}$-hCG) and pregnancy-specific ${eta}_1$-glycoprotein($SP_1$) levels were determined more than one per week during 11-41 days post embryo transfer(ET) in 21 consecutive pregnancies after in vitro fertilization(IVF), which included 8 normal singleton pregnancies, 3 twin pregnancies, 4 clinical abortions, 1 ectopic pregnancy, and 5 preclinical abortions. The sensitivity of serum ${eta}$-hCG and $SP_1$ radioimmunoassays was 3mIU/ml and 0.7ng/ml relatively. At the 7th to 8th week of gestation, ultrasonographic confirmation of fetal pole and fetal heartbeat was performed. Both serm ${eta}$-hCG and $SP_1$ levels showed logarithmic increase, but log[$SP_1$] had more steep rising curve and had wider variation than log[${eta}$-hCG] in normal singleton pregnancies. In 3 twin pregnancies and one ectopic pregnancy, both serum ${eta}$-hCG and $SP_1$ levels located within the 95% confidence interval of the mean levels of 8 normal singleton pregnancies(normal range). In 2 clinical abortions which had a fetal pole without heartbeat, serum ${eta}$-hCG level showed lower limit of the normal range or just below, but all $SP_1$ levels showed within the normal range. In other 2 clinical abortions which were diagnosed as blighted ovum, both serum ${eta}$-hCG levels from 11 days post-ET and serum $SP_1$ levels from later days compared with ${eta}$-hCG were below the normal range. In 5 preclinical abortions, serum $SP_1$ levels were within the normal range but serum ${eta}$-hCG levels were far below the normal range. In conclusion, both serum ${eta}$-hCG and $SP_1$ levels increased exponentially with similar pattern in normally conceived pregancy after IVF-ET. Both serum ${eta}$-hCG and $SP_1$ levels could predict outcome of early pregnancy to a certain degree, but log[${eta}$-hCG] levels had more significant correlation with outcome of pregnancy compared with log[$SP_1$] levels. In addition, ultrasonographic examination of fetal poles and fetal heartbeats gives very important clinical information and prognosis.