Abstract
In a group of 20 asymptomatic women at increased risk for ectopic pregnancy, serum analyses were conducted prospectively early in pregnancy (amenorrhea ≤45 days) at 2-4-day intervals, to examine the rate of increase in hCG values. The initial serum hCG level, which was determined at the time of the first transvaginal ultrasound examination, was below the discriminatory zone of 1000 IU/I (2nd International Standard). In 8 out of the 9 women who were ultimately diagnosed as having an ectopic pregnancy, the increase in hCG progressed only slowly, with a doubling time exceeding 2. 2 days. This slow hCG increase occurred in 2 out of the 11 women who were ultimately diagnosed as having an intra-uterine pregnancy; both women subsequently had an early spontaneous abortion. When Lindblom's hCG score was applied retrospectively to distinguish between intra-uterine and ectopic pregnancies, the hCG increase in all the ectopic pregnancies was below 190 IU/I per day and in 10 of the 11 women with an intra-uterine pregnancy above 190 IU/I per day. A slower rate of increase was observed in only one woman with an intra-uterine pregnancy; she had a spontaneous abortion. The doubling time of hCG and the hCG score are useful diagnostic aids in cases where transvaginal ultrasound has not (yet) given a definite answer regarding the presence of an intra-uterine pregnancy.