Declining serum concentrations of the beta-subunit of human chorionic gonadotropin and ruptured ectopic pregnancy.

Declining values of the beta-subunit of human chorionic gonadotropin may be associated with ectopic pregnancy or missed abortion. Sonography may not always establish a definitive diagnosis. A case is presented where expectant management of declining levels resulted in rupture of an ectopic pregnancy. Declining values of the beta-subunit of human chorionic gonadotropin should not give the clinician a false sense of security in managing first-trimester pregnancy disorders.