Objective
We sought to determine utility of uterine evacuation for diagnosis of nonviable pregnancy of unknown location (PUL).
Study Design
We conducted a cohort study to assess the prevalence of ectopic pregnancy (EP), overall, and stratified by presenting signs and symptoms in women with a nonviable PUL.
Results
Of the 173 women, 66 (38%) had miscarriage (spontaneous abortion [SAB]) and 107 (62%) had EP. When initial human chorionic gonadotropin (hCG) was <2000 mIU/mL, the odds of an EP were greater (odds ratio, 4.32; 95% confidence interval, 2.04–9.12). Demographic factors, obstetric history, and clinical presentation were not useful in distinguishing between EP and SAB. Pre-evacuation hCG increase had strong trend association with EP (odds ratio, 2.14; 95% confidence interval, 0.98–4.68). A >30% fall in postcurettage hCG was suggestive, but was not a diagnostic indicator of SAB.
Conclusion
Uterine evacuation is a useful diagnostic aid for women with nonviable PUL. Nondiagnostic ultrasound findings and absolute and serial hCG values are associated with, but do not accurately predict final diagnosis.
Women at risk of ectopic pregnancy (EP) may present with pain and bleeding in the first trimester of pregnancy. The early diagnosis of an EP in these women reduces the risk of a ruptured EP (a leading cause of maternal mortality that accounts for 10% of all maternal deaths) and improves the future fertility outcomes in 6% of the women who are more likely to be diagnosed with a future EP. Currently, the diagnosis of an EP requires multiple office visits, serial blood tests for up to a 6-week period, multiple ultrasound examinations, and may entail surgical procedures such as uterine curettage and laparoscopy before a definitive diagnosis can be established.
In practice, ultrasound scans can help predict the location of a pregnancy in 69-92% of patients seen in specialty centers. The concept of a discriminatory zone (DZ) with regard to human chorionic gonadotropin (hCG) level is intimately linked to the accuracy of ultrasound and ranges from 1500-2500 IU/L. All cases with a nondiagnostic ultrasound (the absence of visualization of either an intrauterine or extrauterine pregnancy with a transvaginal ultrasound examination) are defined as pregnancy of unknown location (PUL). A total of 50-70% PUL resolve spontaneously, about 30% are diagnosed as an intrauterine pregnancy (of which 2/3 are viable intrauterine pregnancies), and almost 7-20% are subsequently diagnosed as EP.
Controversy exists in the management of women with a nonviable PUL. Uterine evacuation may be used to distinguish an intrauterine pregnancy from an EP. Other authors have suggested that persistent PULs should be treated as ultrasonically missed EP. A presumed diagnosis of an EP is often made when a woman has no evidence of an IUP with an hCG above a DZ, or when serial hCG values have plateaued. We have previously reported that up to 40% of women with such a presumed diagnosis of EP actually have a nonviable intrauterine gestation. If distinction is not made between these 2 diagnoses, women with a spontaneous abortion (SAB) (miscarriage) may be treated as if they had and an EP. Given improved resolution of ultrasound machines in the past decade, the aim of this study was to validate these findings in a new cohort of women, presenting with first-trimester PUL and pain, bleeding, or both.
The objective of this study to determine utility of uterine evacuation for diagnosis of nonviable PUL and evaluate if characteristics at initial presentation (clinical symptoms, historical variables, laboratory results of hCG values, and ultrasound examination) can aid in distinguishing between a woman with an EP or a miscarriage.
Materials and Methods
Approval to conduct this study was obtained from the Institutional Review Board of the University of Pennsylvania. A database is maintained at the University of Pennsylvania of all women in the first trimester of pregnancy (with a positive pregnancy test result or history of a missed period) who present to the emergency department with pain, bleeding, or both. Clinical and demographic data were entered directly into the computerized database by clinical staff caring for the patient.
The population for this study included women with a nonviable PUL from December 2003 through July 2007. Specifically, women evaluated were clinically stable with an initial hCG level ≥2000 mIU/mL at presentation and a nondiagnostic ultrasound, or had an abnormal rise/fall/plateau of serial hCG levels with the initial hCG value <2000 mIU/mL. During the study period, it was standard clinical practice for clinicians to perform a uterine evacuation prior to medical treatment for a presumed EP. The technique for uterine evacuation was at the discretion of the treating physician. The procedure performed was either a manual vacuum aspiration or electric vacuum aspiration with general anesthesia or conscious sedation. The techniques of these procedures have been described previously.
Potential predictors of clinical outcome were identified from the medical and surgical history, clinical presentation, and diagnostic tests. History included patient age, race, gravidity, parity, number of live births, number of SAB, elective abortions, and previous EP. Findings at presentation analyzed as predictors included length of amenorrhea, amount of bleeding, pain, and hCG level. Bleeding was categorized as none, mild, moderate, or severe (no bleeding and less than, equal to, or more than regular menstrual bleeding, respectively) as reported by the patient. Pain was self-reported.
Women were followed in the clinical database until they were definitively diagnosed with an EP or a nonviable intrauterine pregnancy. Diagnosis of a nonviable intrauterine pregnancy was confirmed by report of histopathology of products of conception obtained from uterine evacuation or postoperative resolution of serum hCG levels (hCG levels were followed serially until <5 mIU/mL). The diagnosis of an EP was confirmed by the presence of chorionic villi in the fallopian tube, by visualizing an extrauterine gestational sac (with yolk sac or embryonic cardiac activity) with ultrasound, or by postoperative rise in hCG level after dilation and evacuation concomitant with no evidence of chorionic villi in endometrial curettage samples (ie, nonvisualized EP). The majority of postoperative hCG values were drawn on days 1 or 2 following the procedure. The values presented have been normalized to 1 day changes.
Statistical analysis
Comparisons between groups (women with a final diagnosis of EP vs nonviable intrauterine pregnancies) were performed using a Student t test for continuous variables. For variables with nonnormal distributions, medians and interquartile range are reported and the Wilcoxon nonparametric test was utilized to determine statistical significance. The χ 2 tests were used to compare categorical variables and Fisher’s exact test was utilized when cell counts were ≤5. Statistical analysis was performed using software (SAS; SAS Institute Inc, Cary, NC) and a 2-tailed P value < .05 was considered statistically significant.
Results
A total of 173 women were included in the study. Of these, 66 (38%) women were ultimately diagnosed with SAB and 107 (62%) with an EP. None of the patients had serious adverse outcomes.
The first step was to describe and compare the general characteristics of women based on final diagnosis. The demographic information and obstetric histories of the 2 groups are presented in Table 1 and are stratified by ultimate outcome. The mean age, race, and obstetric history were similar in both groups. Obstetric history data (gravidity, parity, history of live birth, past miscarriage, previous voluntary interruption of pregnancy, and history of EP) were not associated with final diagnosis of EP or miscarriage.
| Variable | Miscarriagen = 66 | Ectopicn = 107 | P value |
|---|---|---|---|
| Age, y a | 29.4 ± 6.6 | 29.9 ± 7.0 | .64 |
| Race, b | .43 | ||
| Caucasian | 5 (7.5) | 8 (7.5) | |
| African American | 39 (54.5) | 48 (49.5) | |
| Other | 1 (2.2) | 5 (8.2) | |
| Gravidity b | 3 [1-5] | 3 [1-4] | .19 |
| Parity b | 1 [0-2] | 1 [0-2] | .42 |
| No. of live births b | 1 [0-2] | 1 [0-2] | .54 |
| History of spontaneous miscarriage | 11 (16.7%) | 18 (16.8%) | .86 |
| History of voluntary interruption of pregnancy | 15 (22.3%) | 21 (19.3%) | .42 |
| History of ectopic pregnancy | 4 (6.0%) | 6 (5.6%) | 1.0 |
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