Transvaginal Sonogram May Be Best Test for Ectopic Pregnancy

Laurie Barclay, MD

April 23, 2013

Transvaginal sonography is the single best diagnostic test to assess suspected ectopic pregnancy, according to a systematic review published in the April 24 issue of JAMA. Clinical history and physical examination alone are insufficient to confirm or rule out ectopic pregnancy in women with abdominal pain or vaginal bleeding during early pregnancy.

"The rapid identification and accurate diagnosis of women who may have an ectopic pregnancy is critically important for reducing the maternal morbidity and mortality associated with this condition," write John R. Crochet, MD, from the Center of Reproductive Medicine in Webster, Texas, and colleagues.

Ectopic pregnancy occurs in up to 2.6% of all pregnancies and is the chief cause of first-trimester pregnancy-related mortality, accounting for up to 6% of maternal deaths. However, less than half of women with ectopic pregnancy have characteristic symptoms of abdominal pain and vaginal bleeding, which are more likely to indicate miscarriage.

The study goal was to review the diagnostic value of the patient history, physical examination, readily available laboratory testing, and sonography in detecting ectopic pregnancy in women with abdominal pain or vaginal bleeding in early pregnancy.

Dr. Crochet and colleagues searched MEDLINE and EMBASE from 1965 to December 2012 for English-language articles on the diagnosis of ectopic pregnancy. Inclusion criteria were prospective design, sample size of at least 100 or more pregnant women with abdominal pain or vaginal bleeding, and comparison of history, physical examination, laboratory findings, and sonography with a reference standard. That standard could be direct surgical visualization of ectopic pregnancy or clinical follow-up for all pregnancies to confirm that ectopic pregnancy was not missed.

Although the search identified 10,890 articles, only 14 studies met the inclusion criteria. These studies enrolled a total of 12,101 patients. Two reviewers independently extracted data and evaluated methodological quality, and a third reviewer resolved any discrepancies.

Transvaginal sonography findings of an adnexal mass in the absence of an intrauterine pregnancy had a positive likelihood ratio (LR+) of 111 (95% confidence interval [CI], 12 - 1028; n = 6885). Conversely, transvaginal sonography showing normal adnexa was associated with lower likelihood of ectopic pregnancy (negative LR [LR−], 0.12; 95% CI, 0.03 - 0.55; n = 6885).

LR+ was less than 1.5 for all components of the patient history. Physical examination findings associated with greater likelihood of ectopic pregnancy were cervical motion tenderness (LR+, 4.9; 95% CI, 1.7 - 14; n = 1435), adnexal mass (LR+, 2.4; 95% CI, 1.6 - 3.7; n=1378), and adnexal tenderness (LR+, 1.9; 95% CI, 1.0 - 3.5; n = 1435).

"Existing studies do not establish a single serum human chorionic gonadotropin (hCG) level that is diagnostic of ectopic pregnancy," the reviewers write.

"Transvaginal sonography is the single best diagnostic modality for evaluating women with suspected ectopic pregnancy. The presence of abdominal pain or vaginal bleeding during early pregnancy should prompt a transvaginal sonogram and quantitative serum hCG testing."

They conclude, "Patients with signs and symptoms of excessive blood loss or hemodynamic collapse should immediately have gynecological evaluation."

The authors have disclosed no relevant financial relationships.

JAMA. 2013;309:1722-1729. Abstract