Jouppila P, Tapanainen J, Huhtaniemi I
Eur J Obstet Gynecol Reprod Biol. 1980 Jan;10(1):3-12. doi: 10.1016/0028-2243(80)90031-3.
The value of plasma hCG determinations (based on the recognition of beta-subunit of hCG) and ultrasound was examined in 48 cases of suspected ectopic pregnancy. In 11 patients with the final diagnosis of ectopic pregnancy (23%), the plasma hCG was clearly subnormal (0.37-3.96 IU/ml), with only one exception, where a normally developed fetus was operated from the fallopian tube (hCG 21.1 IU/ml in the 8th wk). The plasma hCG lvels allowed differentiation of the non-pregnant cases from the normal intrauterine pregnancies and the ectopic cases, but not ata all between the different forms of intrauterine early pregnancy failures and ectopic pregnancies. By ultrasound, however, it was possible to reliably diagnose intrauterine pregnancies from the 7th wk of amenorrhea onwards, and to classify them into the normal and pathological subgroups. The direct demonstration of ectopic pregnancy by ultrasound is problematic, but the exclusion of intrauterine pregnancy by this method, combined with the simultaneous plasma hCG determination by sensitive and rapid method, can be recommended for primary examinations in suspected ectopic pregnancy.
