Ectopic pregnancy: changes in serum human chorionic gonadotropin concentration.

In 93 patients with surgically proved ectopic gestation, the initial serum beta-human chorionic gonadotropin (hCG) concentration ranged from 2.0 to 5260 ng/ml; in 33 (35%) the values were below 100 ng/ml. Of 25 patients with serial hCG data, 20 showed a plateau or fall in serum concentrations over at least 48 hours, thereby identifying the gestation as nonviable. Sixty-four patients underwent sonographic evaluation; 35 of these also underwent at least one quantitated hCG determination. Correlating a single hCG value with the sonographic diagnosis correctly identified the gestation as nonviable in 21% of the cases, but a definite diagnosis was not possible in the rest. For the clinically stable patient with a suspected ectopic pregnancy, serial hCG determinations offer a useful technique for evaluating gestational viability.