Objective: To analyze serial human chorionic gonadotropin (hCG) levels in women presenting to the emergency department who were ultimately confirmed to have ectopic pregnancies.
Methods: Human chorionic gonadotropin levels were obtained over time until definitive diagnosis. To be included, women had to have at least 2 hCG measurements. Human chorionic gonadotropin curves were characterized and their slopes calculated.
Results: Two hundred women received diagnoses of ectopic pregnancy with the help of serial hCG values and were included in the study. No curve adequately characterized the pattern of hCG values so attention was focused on the initial 2 values. The median slope of log hCG among all subjects was 0.11 (25% increase in 2 days). However, 60% of subjects had an initial rise in hCG, and 40% had an initial fall. The rise in hCG for women with ectopic pregnancies (0.28; 75% increase in 2 days) was slower than the mean increase reported for a viable intrauterine pregnancy. The decline in hCG for women with ectopic pregnancies (-0.225; 27% decline in 2 days) was slower than the mean reported for completed spontaneous abortion. However, 20.8% of women presented with a rise in hCG values similar to the minimal rise for women with a viable gestation, and 8% of women presented with a fall in hCG values similar to women with a completed spontaneous abortion.
Conclusion: There is no single way to characterize the pattern of hCG for ectopic pregnancy. The number of women with ectopic pregnancy who experience an increase in hCG values is approximately equal to the number of those who experience a decrease. The hCG profile in women with ectopic pregnancy can mimic that of an intrauterine pregnancy or a completed spontaneous abortion in approximately 29% of cases.
Level of evidence: II-2.