Diagnosis of ectopic pregnancy--why we need a protocol

To audit the management after instituting a screening programme for ectopic pregnancy in an institution with a protocol utilising ultrasound examination and serial human chorionic gonadotropin (hCG) and to examine the risk of missed diagnosis with deviation from the protocol.

A retrospective analysis of the management of 145 symptomatic patients in early pregnancies without intrauterine gestational sacs from ultrasound examinations, during the period April to June 1994 in Kandang Kerbau Hospital. Patients underwent serial hCG tests over 48 hours with or without repeat ultrasound scans before definitive treatment unless clinical indications for emergency surgery was necessary.

There were 35 ectopic pregnancies (24%), 16 were viable intrauterine pregnancies (11%), 87 were non-viable pregnancies (60%) and 7 were of unknown outcome. There were much practice deviations from the protocol. Forty-four percent (64 cases) of the management decisions were made based on the initial clinical and ultrasound findings, and another 14% (21 cases) after a repeat assessment within the next day by either a repeat scan or serial serum hCG over one day. Among them, two of the 29 operated for suspected ectopic pregnancy were not ectopic (7%) and two of the 56 thought not to be ectopic, turned out to be ectopic (4%) (p < 10(-8)). Six percent (8 cases) defaulted after the initial assessments and one of them was found to be ectopic subsequently. Thirty percent (43 cases) adhered to the protocol. They had serial serum hCG done over two days. Seven of them requiring further repeats of serial serum hCG before management decisions were made. Four patients who were operated on were confirmed ectopic and 39 patients not operated on were not ectopic. Three percent (5 cases) were managed by serial hCG over 3 to 5 days and another 3% (4 cases) by repeating scan over one to two weeks without serial hCG. None of these was ectopic. The percentage change of hCG levels over two days gave indications of the likely diagnosis.

Adhering to a protocol utilising the principle of ultrasound scan, serial hCGs and selective repeat ultrasound scans are highly recommended for the diagnosis of ectopic pregnancy. Any deviation from protocol is dangerous, with a 4% risk of missing an ectopic and a 7% risk of unnecessary operation for suspected ectopic pregnancy.