A presumptive diagnosis of ectopic pregnancy (EP) in women with pregnancy of unknown location is often inaccurate, and if these women are clinically stable they should undergo dilation and curettage (D&C), according to a paper in Fertility and Sterility.
D&C would avoid misdiagnosis and unnecessary exposure to methotrexate, the authors say. In research reported in 2002, 40% of presumed EP diagnoses were incorrect. And in the current study, a presumptive EP diagnosis was inaccurate for 27% of the women.
"This false diagnosis rate is substantial," said Dr Karine Chung of the Los Angeles County-University of Southern California Medical Center and her colleagues. "This is especially notable when the initial human chorionic gonadotropin (hCG) is above the discriminatory zone and the 'true positive' rate is just over 57%."
Many doctors give methotrexate in all cases of suspected EP, even though it carries a major risk for side effects. Dr Chung and colleagues point out that while D&C may cost more, one analysis found it resulted in fewer complications and hospitalizations than empiric methotrexate.
Over the past decade, they add, ultrasound resolution has improved, along with understanding of normal beta-HCG curves – which could mean that EP diagnoses are more accurate today.
To reevaluate the clinical usefulness of D&C in this setting, the research team reviewed records on 321 women who had D&C between 2004 and 2007 either because ultrasonography didn't show an intrauterine pregnancy (IUP) or they had an abnormal hCG trend.
They excluded molar pregnancies, and they also excluded 63 women who had D&C for this indication but for whom records weren't available.
Results of the experiment
On initial ultrasound, the clinical impression was "probable IUP" in 10.6%, "suspicious for EP" in 28.7% and "nondiagnostic" in 60.7%. Ultimately, 73.2% of the women had EP as their final diagnosis, and 26.8% had non-viable IUP.
Women with hCG levels below 2,000 mlU/mL were 3.82 times more likely to have EP. Seventy percent of women with levels below this cutoff had EP, compared to 30% of those with higher levels.
An ultrasound exam showing free fluid in the cul de sac increased the odds of EP 3.78-fold. In addition, the median preoperative endometrial echo complex was thinner in EP than in IUP (7.20 vs. 8.35 mm). These findings "correlated well with the final diagnosis but did not have 100% predictive value," the authors reported.
Conclusion based on the results
They conclude, "D&C remains valuable to differentiate EP from nonviable IUP and to avoid misdiagnosis and unnecessary exposure to methotrexate."
(Reuters Health, July 2011)