Ultrasonographic differentiation of the gestational sac of early intrauterine pregnancy from the pseudogestational sac of ectopic pregnancy

A Lexicon for First-Trimester US: Society of Radiologists in Ultrasound Consensus Conference Recommendations

The Society of Radiologists in Ultrasound convened a multisociety panel to develop a first-trimester US lexicon based on scientific evidence, societal guidelines, and expert consensus that would be appropriate for imagers, clinicians, and patients. Through a modified Delphi process with consensus of at least 80%, agreement was reached for preferred terms, synonyms, and terms to avoid. An intrauterine pregnancy (IUP) is defined as a pregnancy implanted in a normal location within the uterus. In contrast, an ectopic pregnancy (EP) is any pregnancy implanted in an abnormal location, whether extrauterine or intrauterine, thus categorizing cesarean scar implantations as EPs. The term pregnancy of unknown location is used in the setting of a pregnant patient without evidence of a definite or probable IUP or EP at transvaginal US. Since cardiac development is a gradual process and cardiac chambers are not fully formed in the first trimester, the term cardiac activity is recommended in lieu of 'heart motion' or 'heartbeat.' The terms 'living' and 'viable' should also be avoided in the first trimester. 'Pregnancy failure' is replaced by early pregnancy loss (EPL). When paired with various modifiers, EPL is used to describe a pregnancy in the first trimester that may or will not progress, is in the process of expulsion, or has either incompletely or completely passed.

A Lexicon for First-Trimester US: Society of Radiologists in Ultrasound Consensus Conference Recommendations

The Society of Radiologists in Ultrasound convened a multisociety panel to develop a first-trimester US lexicon based on scientific evidence, societal guidelines, and expert consensus that would be appropriate for imagers, clinicians, and patients. Through a modified Delphi process with consensus of at least 80%, agreement was reached for preferred terms, synonyms, and terms to avoid. An intrauterine pregnancy (IUP) is defined as a pregnancy implanted in a normal location within the uterus. In contrast, an ectopic pregnancy (EP) is any pregnancy implanted in an abnormal location, whether extrauterine or intrauterine, thus categorizing cesarean scar implantations as EPs. The term pregnancy of unknown location is used in the setting of a pregnant patient without evidence of a definite or probable IUP or EP at transvaginal US. Since cardiac development is a gradual process and cardiac chambers are not fully formed in the first trimester, the term cardiac activity is recommended in lieu of 'heart motion' or 'heartbeat.' The terms 'living' and 'viable' should also be avoided in the first trimester. 'Pregnancy failure' is replaced by early pregnancy loss (EPL). When paired with various modifiers, EPL is used to describe a pregnancy in the first trimester that may or will not progress, is in the process of expulsion, or has either incompletely or completely passed. © RSNA and Elsevier, 2024 Supplemental material is available for this article. This article is a simultaneous joint publication in Radiology and American Journal of Obstetrics & Gynecology. All rights reserved. The articles are identical except for minor stylistic and spelling differences in keeping with each journal's style. Either version may be used in citing this article. See also the editorial by Scoutt and Norton in this issue.

The incidence and importance of the pseudogestational sac revisited

BACKGROUND

In a pregnancy of unknown location, an intrauterine fluid collection may represent either the early gestational sac of an intrauterine pregnancy, or as reported in previous literature, the pseudogestational sac of an ectopic pregnancy. Various sonographic features have been used to distinguish these 2 entities, but the clinical relevance of the pseudogestational sac remains unclear.

OBJECTIVE

To establish the incidence and relative rate of intrauterine fluid collection among ectopic and intrauterine pregnancies and to determine if the size of the collection differs between ectopic and intrauterine pregnancies STUDY DESIGN: We performed a retrospective cohort study of women with pregnancies of unknown location and pelvic or abdominal pain or bleeding. We calculated the incidences of intrauterine fluid collections among ectopic and intrauterine pregnancies, including both ongoing pregnancies and spontaneous abortions, given that that our focus was location and not viability. We calculated the relative risk of ectopic pregnancy if an intrauterine fluid collection was present, adjusting for age and vaginal bleeding. We compared the incidences of ectopic and intrauterine pregnancies among those with and without intrauterine fluid collections. Among those with collections, we compared the mean sac diameter between ectopic and intrauterine pregnancies in continuous and categorical fashions.

RESULTS

We evaluated 1236 women presenting with a pregnancy of unknown location. The rates of ectopic and intrauterine pregnancies (including spontaneous abortions) were 13.1% and 63.9%, respectively, with the remainder lost to follow-up. On ultrasound, 452 women (36.6%) had an intrauterine fluid collection. Eight of 162 ectopic pregnancies (4.9%) had a collection, compared with 363 of 789 intrauterine pregnancies (46.0%) (P=.01). Of the ectopics with a fluid collection, 5 had an adnexal mass. The presence of intrauterine fluid collection decreased the risk of ectopic pregnancy (adjusted relative risk, 0.09; 95% confidence interval, 0.05-0.19) after adjusting for age and the presence of bleeding. Among those with an intrauterine fluid collection, the rate of ectopic pregnancy was 2.2%, and the rate of intrauterine pregnancy was 97.8%; among those without a collection, the rate of ectopic pregnancy was 26.7%, and the rate of intrauterine pregnancy was 73.3%. The mean sac diameter did not differ between ectopic and intrauterine pregnancies, whether analyzed continuously or categorically.

CONCLUSION

In the presence of an intrauterine fluid collection, the rate of ectopic pregnancy is very low. The size of the intrauterine fluid collection in a woman with a pregnancy of unknown location cannot be used to distinguish between a gestational sac and a pseudogestational sac. Pseudogestational sacs are uncommon and of little clinical consequence. In assessing pregnancies of unknown location, clinicians should incorporate the entire clinical picture, including other sonographic findings, to avoid incorrect or delayed diagnoses.

"Pseudogestational Sac" and Other 1980s-Era Concepts in Early First-Trimester Ultrasound: Are They Still Relevant Today?

OBJECTIVES

To determine whether an intrauterine round or oval fluid collection ("saclike structure") can prove to be either an intrauterine pregnancy or intrauterine fluid in conjunction with an ectopic pregnancy (sometimes termed "pseudogestational sac") and whether ultrasound features, including the presence or absence of an echogenic rim, "double sac sign" (DSS), or "intradecidual sign" (IDS), are helpful for establishing the diagnosis or predicting the prognosis.

METHODS

We identified all sonograms obtained from women with positive serum human chorionic gonadotropin results at our institution between January 1, 2012, and June 30, 2018, meeting the following criteria: presence of an intrauterine saclike structure without a yolk sac or embryo; no extraovarian adnexal mass; and follow-up information identifying the location of the pregnancy as intrauterine or ectopic. Study authors reviewed sonograms in all cases and recorded the following information: presence or absence of each of an echogenic rim around the collection, a DSS, and an IDS, as well as the mean sac diameter. The indications for the initial ultrasound examinations were recorded.

RESULTS

A total of 649 sonograms met the inclusion criteria. Of these, 598 fluid collections showed an echogenic rim, 182 a DSS, and 347 an IDS (findings not mutually exclusive). In all 649 cases, a subsequent sonogram or other clinical follow-up confirmed that the patient had an intrauterine pregnancy. That is, none of the fluid collections proved to be a pseudogestational sac. In total, 41.2% were live at the end of the first trimester, and 58.8% miscarried. The prognosis was better in cases with, compared to without, an IDS (P = .01, χ² ), but no ultrasound feature was clinically useful for ruling in or excluding a good prognosis.

CONCLUSIONS

In a woman with positive human chorionic gonadotropin results and no extraovarian adnexal mass, the ultrasound finding of an intrauterine saclike structure is virtually certain to be a gestational sac. Ultrasound features of the structure are of no diagnostic or clinically useful prognostic value. Concepts introduced 30 to 40 years ago when ultrasound equipment had far lower resolution than currently, including a DDS, an IDS, and a pseudogestational sac, have no role today in assessing early pregnancy.

Use of double decidual sac sign to confirm intrauterine pregnancy location prior to sonographic visualization of embryonic contents

OBJECTIVES

To determine the diagnostic accuracy of the double decidual sac sign (DDSS) for predicting an intrauterine pregnancy (IUP) prior to visualization of embryonic contents, using modern high-resolution transvaginal sonography (TVS).

METHODS

The study was conducted following STARD guidelines and participants were recruited prospectively from Nurture Fertility, Nottingham, UK, following in-vitro fertilization/intracytoplasmic sperm injection treatment between 1 January 2015 and 31 October 2015. Women were excluded if there was no evidence of intrauterine fluid collection during the index test, a yolk sac or fetal pole was visible during the index test, no outcome data were available or pregnancy location could not be determined by the reference standard. The index test consisted of TVS at 32-34 days' gestation using a high-frequency transvaginal probe. Reference standard was TVS at 7 weeks' gestation. The outcome of interest was an IUP.

RESULTS

A total of 67 intrauterine fluid collections were observed and included in the analysis, of which 61 exhibited the DDSS and 65 were proven to be IUPs. Two ectopic pregnancies were included, neither of which demonstrated the DDSS. The DDSS therefore had a sensitivity of 93.9% (95% CI, 85.0-98.3%), specificity of 100% (95% CI, 15.8-100%) and overall diagnostic accuracy of 94.0% (95% CI, 88.3-99.7%) for predicting an IUP. The negative likelihood ratio and positive and negative predictive values were 0.06 (95% CI, 0.02-0.16), 100% (95% CI, 94.1-100%) and 33.3% (95% CI, 4.3-77.7%), respectively.

CONCLUSION

With modern high-resolution TVS, presence of the DDSS can be used to confirm accurately IUP location prior to sonographic visualization of embryonic contents, and therefore to exclude effectively ectopic pregnancy. Absence of the DDSS, however, does not preclude an IUP. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Accuracy of first-trimester ultrasound in diagnosis of intrauterine pregnancy prior to visualization of the yolk sac: a systematic review and meta-analysis

OBJECTIVES

To evaluate the diagnostic accuracy of ultrasound in predicting the location of an intrauterine pregnancy before visualization of the yolk sac is possible.

METHODS

This was a systematic review conducted in accordance with the PRISMA statement and registered with PROSPERO. We searched MEDLINE, EMBASE and The Cochrane Library for relevant citations. Studies were selected in a two-stage process and their data extracted by two reviewers. Accuracy measures were calculated for each ultrasound sign, i.e. gestational sac, double decidual sac sign, intradecidual sign, chorionic rim sign and yolk sac. Individual study estimates were plotted in summary receiver-operating characteristics curves and forest plots for examination of heterogeneity. The quality of included studies was assessed.

RESULTS

Seventeen studies including 2564 women were selected from 19 959 potential papers. Following meta-analysis, the presence of a gestational sac on ultrasound examination was found to predict an intrauterine pregnancy with a sensitivity of 52.8% (95% CI, 38.2-66.9%) and specificity of 97.6% (95% CI, 94.3-99.0%). The corresponding performance of the double decidual sac sign, intradecidual sign, chorionic rim sign and yolk sac were: 81.8% (95% CI, 68.1-90.4%) and 97.3% (95% CI, 76.1-99.8%); 66.1% (95% CI, 58.9-72.8%) and 100% (95% CI, 91.0-100%); 79.9% (95% CI, 73.0-85.7%) and 97.1% (95% CI, 89.9-99.6%); and 42.2% (95% CI, 27.7-57.9%) and 100% (95% CI, 54.1-100%), respectively.

CONCLUSION

Visualization of a gestational sac, double decidual sac sign, intradecidual sign or chorionic rim sign increases the probability of an intrauterine pregnancy but is not as accurate for diagnosis as the detection of the yolk sac. However, the findings were limited by the small number and poor quality of the studies included and heterogeneity in the index test and reference standard.

The history of imaging in obstetrics

During the past century, imaging of the pregnant patient has been performed with radiography, scintigraphy, computed tomography, magnetic resonance imaging, and ultrasonography (US). US imaging has emerged as the primary imaging modality, because it provides real-time images at relatively low cost without the use of ionizing radiation. This review begins with a discussion of the history and current status of imaging modalities other than US for the pregnant patient. The discussion then turns to an in-depth description of how US technology advanced to become such a valuable diagnostic tool in the obstetric patient. Finally, the broad range of diagnostic uses of US in these patients is presented, including its uses for distinguishing an intrauterine pregnancy from a failed or ectopic pregnancy in the first trimester; assigning gestational age and assessing fetal weight; evaluating the fetus for anomalies and aneuploidy; examining the uterus, cervix, placenta, and amniotic fluid; and guiding obstetric interventional procedures.

Bedside ultrasonography for obstetric and gynecologic emergencies

There has been an increase in the availability and use of bedside ultrasonography in the acute care setting. The approach to the female patient with a pelvic complaint (including pelvic pain, vaginal bleeding, vaginal bleeding in pregnancy, or vaginal discharge) has been transformed by the use of bedside ultrasonography. Providers familiar with the transabdominal and transvaginal (endocavitary) ultrasonographic examination can obtain more accurate information faster, thereby improving time to consultation or discharge and achieving an increase in patient satisfaction. This article reviews the use of ultrasonography for evaluation of obstetric and gynecologic complaints in the acute care setting.

Double sac sign and intradecidual sign in early pregnancy: interobserver reliability and frequency of occurrence

OBJECTIVES

To assess the interobserver agreement, frequency of occurrence, and prognostic importance of the double sac sign (DSS), intradecidual sign (IDS), and other sonographic findings in early intrauterine pregnancies.

METHODS

We retrospectively identified all sonograms obtained between January 1, 2006, and December 31, 2011, in which: (1) the scan demonstrated an intrauterine fluid collection without a yolk sac or embryo; (2) a follow-up scan confirmed an intrauterine pregnancy; and (3) the first-trimester outcome was known. Each coinvestigator characterized the 199 study sonograms as demonstrating or not demonstrating a DSS or an IDS, based on judgment about whether the scan met published criteria defining these signs.

RESULTS

Interobserver agreement was poor for the DSS (κ= 0.24) and IDS (κ= 0.23). Scans frequently demonstrated neither sign: 150 cases (75.4%) if we considered a sign to be present when both investigators graded it as present and 69 cases (34.7%) using the looser criterion that either graded it as present. The presence of a DSS or an IDS was unrelated to the β-human chorionic gonadotropin (β-hCG) value (P > .05, t test, all comparisons). An inner echogenic ring was present in 158 cases (79.4%), and the decidua was brighter peripherally than centrally in 102 (51.3%). The first-trimester outcome was unrelated to the presence of a DSS or an IDS, presence of an inner echogenic ring, or decidual appearance (P > .05, χ(2), all comparisons).

CONCLUSIONS

The sonographic appearance of early gestational sacs, before visualization of a yolk sac or embryo, is highly variable. The DSS and IDS are often absent; there is poor interobserver agreement regarding these signs; and the prognosis is unrelated to their presence or absence. A round or oval intrauterine fluid collection in a woman with positive β-hCG should be treated as a gestational sac until proven otherwise, regardless of whether it demonstrates a DSS or an IDS.

Sonography in first trimester bleeding

Vaginal bleeding is the most common cause of presentation to the emergency department in the first trimester. Approximately half of patients with first trimester vaginal bleeding will lose the pregnancy. Clinical assessment is difficult, and sonography is necessary to determine if a normal fetus is present and alive and to exclude other causes of bleeding (eg, ectopic or molar pregnancy). Diagnosis of a normal intrauterine pregnancy not only helps the physician in terms of management but also gives psychologic relief to the patient. Improved ultrasound technology and high-frequency endovaginal transducers have enabled early diagnosis of abnormal and ectopic pregnancies, decreasing maternal morbidity and mortality. The main differential considerations of first trimester bleeding are spontaneous abortion, ectopic pregnancy, or gestational trophoblastic disease. This article reviews the causes of first trimester bleeding and the sonographic findings, including normal features of first trimester pregnancy.

First-trimester ultrasound: current uses and applications

This article is aimed to aid the sonographer and medical care provider in better interpretation and clinical application of first-trimester ultrasound findings in early pregnancy. We review current uses, applications, and interpretations of first-trimester ultrasound. A discussion of basic embryology and normal as well as abnormal first-trimester sonographic findings are discussed. We also cover the utility of the first-trimester ultrasound in screening for fetal aneuploidy. Attention is also given to the role of the first-trimester ultrasound in the prediction of adverse perinatal and maternal outcomes.

Serum biochemistry correlates with the size of tubal ectopic pregnancy on sonography

OBJECTIVE

To investigate whether there is a correlation between serum biochemistry (human chorionic gonadotropin (hCG), CA 125, progesterone and estradiol) and the common sonographic findings (blob sign, bagel sign or extrauterine gestational sac with cardiac activity) or size of a tubal ectopic pregnancy, and whether there is a difference in serum biochemistry between women with a tubal ectopic pregnancy who are hemodynamically unstable (tachycardia, hypotension, falling hemoglobin levels and/or acute severe abdominal pain) and those who are hemodynamically stable.

METHODS

This was a prospective cohort study of 106 women with a tubal ectopic pregnancy. We noted transvaginal ultrasound examination findings including adnexal mass size, and the serum levels of hCG, CA 125, progesterone and estradiol. The data were analyzed retrospectively.

RESULTS

The mean maternal and gestational ages were 30.7+/-5.7 years and 44+/-4.2 days, respectively. There was no correlation between serum markers and common sonographic findings. However, in the presence of the bagel sign on ultrasound, hemodynamic stability was more common (P=0.03). The mean serum hCG concentrations in tubal ectopic pregnancies<20 mm, 20-40 mm and >40 mm in size were 2225.3+/-3166.9, 4124.8+/-6121.4, and 11 011.8+/-12 670.1 IU/mL, respectively (P<0.001). Serum hCG, CA 125 and estradiol values were well correlated with adnexal mass size; for CA 125 this correlation was linear. There was no difference in serum biochemistry between hemodynamically stable and hemodynamically unstable women.

CONCLUSION

Common sonographic findings of tubal ectopic pregnancy do not correlate with serum biochemistry. High levels of CA 125, hCG or estradiol may suggest a larger adnexal mass in women with uncomplicated tubal pregnancies. Hemodynamically stable and hemodynamically unstable women do not differ in their serum biochemistry.

Ultrasound evaluation of first trimester pregnancy complications

OBJECTIVE

To review the biological effects and safety of obstetric ultrasound.

OUTCOME

Outline the circumstances in which safety may be a concern with obstetric ultrasound.

EVIDENCE

Medline was searched, and a review of a document on this subject published by Health Canada and of bibliographies from identified articles was conducted.

VALUES

Review by principal authors and the Diagnostic Imaging Committee of the SOGC. The level of evidence was judged as outlined by the Canadian Task Force on the Periodic Health Examination.

BENEFITS, HARMS AND COSTS

Obstetric ultrasound should only be done for medical reasons, and exposure should be kept as low as reasonably achievable (ALARA) because of the potential for tissue heating. Higher energy is of particular concern for pulsed Doppler, colour flow, first trimester ultrasound with a long transvesical path (> 5 cm), second or third trimester exams when bone is in the focal zone, as well as when scanning tissue with minimal perfusion (embryonic) or in patients who are febrile. Operators can minimize risk by limiting dwell time, limiting exposure to critical structures, and following equipment generated exposure information. Recommendations 1. Obstetric ultrasound should only be used when the potential medical benefit outweighs any theoretical or potential risk (II-2A). 2. Obstetric ultrasound should not be used for nonmedical reasons, such as sex determination, producing nonmedical photos or videos, or for commercial purposes ( III-B). 3. Ultrasound exposure should be as low as reasonably achievable (ALARA) because of the potential for tissue heating when the thermal index exceeds 1. Exposure can be reduced through the use of output control and (or) by reducing the amount of time the beam is focused on one place (dwell time) (II-1A). 4. All diagnostic ultrasound devices should comply with the output display standards (MI and TI) (III-B). 5. When ultrasound is done for research or teaching purposes, exposed individuals should be informed if either the MI or TI are greater than 1 and how this exposure compares to that found in normal diagnostic practice (III-B). 6. While imaging the fetus in the first trimester, Doppler and colour Doppler should be avoided (III-B).

Famine, social disruption, and involuntary fetal loss: evidence from Chinese survey data

Relying on half a million pregnancy histories collected from Chinese women in the late 1980s, we studied nearly a quarter century of self-reported miscarriages and stillbirths in China. Our results suggest that these two forms of involuntary fetal loss are affected not only by biological and demographic factors, such as the mother's age, pregnancy order, and pregnancy history, but also by the mother's social characteristics and the larger social environment. In this article, we focus on how two social and economic crises--the Great Leap Forward famine and the Cultural Revolution--resulted in elevated risks of miscarriage and stillbirth in the Chinese population.

Ultrasound in pregnancy

Ultrasound represents the cornerstone of the emergent evaluation of pregnancy-related complaints. Knowledge of the potential and the limitations of this imaging modality, regardless of who performs it, is important for physicians who evaluate and manage these patients and their unborn children in the ED.

Ectopic pregnancy diagnosis and the pseudo-sac

OBJECTIVE

To evaluate the impact of an ultrasound finding of a pseudo-sac (PS), a uterine sac without a double decidual ring or a yolk sac, on the management of cases with possible ectopic pregnancy.

DESIGN

A retrospective review of a series of cases.

SETTING

A general hospital.

PATIENT(S)

Seventy-seven patients who had a diagnostic laparoscopy over a period of 3 years for suspected ectopic pregnancy.

MAIN OUTCOME MEASURE(S)

A logistic regression analysis was conducted to evaluate the effect of the ultrasound finding of a PS on predicting a negative finding at laparoscopy.

RESULT(S)

The report of a PS is significantly associated with a false-positive diagnosis of ectopic pregnancy.

CONCLUSION(S)

A diagnosis of PS should not be interpreted as indicative of an ectopic pregnancy because radiological differentiation between an early intrauterine pregnancy failure and an ectopic pregnancy is not possible.

Ultrasound of the acute female pelvis

Ultrasound is the most valuable imaging modality in evaluating the premenopausal female presenting with acute pelvic pain. The appropriate interpretation of the ultrasound study requires correlation with the patient's clinical history and laboratory values. This is especially true of the serum beta-hCG, where ultrasound relies on this test to make the diagnosis of ectopic pregnancy. When the serum test for pregnancy is negative and the patient has an adnexal mass this could be secondary to a complicated ovarian cyst (hemorrhage, rupture), ovarian torsion or pelvic inflammatory disease. The ultrasound image can usually make the diagnosis in conjunction with the clinical papameters, however, this is most difficult in patients with ovarian torsion.

Ectopic pregnancy from surgical emergency to medical management

During the past 25 years, the incidence of ectopic pregnancy has progressively increased while the morbidity and mortality have substantially decreased, and the treatment has progressed from salpingectomy by laparotomy to conservative surgery by laparoscopy and more recently to medical therapy. This therapeutic transition from surgical emergency to medical management has been attributed to early diagnosis through the use of sensitive assays for hCG and the high definition of vaginal ultrasound. By using these sensitive diagnostic tools, we are now able to select those patients who are most likely to respond to medical management versus those who are at high risk of rupture and require surgery. Besides being less invasive and associated with significantly lower risks, medical therapy with methotrexate results in significant cost savings, which have been calculated to be approximately $3,000 per treated patient. Our goal is to identify those patients with ectopic pregnancy who are most likely to respond to methotrexate therapy and least likely to develop significant side effects. Recent studies have helped us define the predictors of success with methotrexate treatment in women with ectopic pregnancy. The reported success rates of treating ectopic pregnancy with methotrexate vary from 71% to 100%. The highest success rates have been reported from institutions that have detailed diagnostic and therapeutic protocols, readily available assays for serum hCG levels, high-resolution vaginal probe ultrasound, and support staff that can closely monitor clinical response. The importance of developing specific protocols to create a clinical environment that supports the effective use of medical therapy for ectopic pregnancy is confirmed by the associated cost savings, decreased morbidity, and patient preference. Modern diagnostic advances and minimally invasive treatments coupled with improved success rates for assisted reproductive technologies should reduce the morbidity and mortality associated with ectopic pregnancy and offer the affected couple a much more optimistic outlook for subsequent reproductive potential.

Some misconceptions and pitfalls in ultrasonography

There are many misconceptions in the field of ultrasonography. Some are because of poor understanding of anatomy and/or embryological or developmental features of certain organs, which have prevailed over the course of the centuries since the discovery of these entities (e.g., column of Bertin and hypertrophic column of Bertin). Some misconceptions derived from misinterpretation (e.g., double decidual sac sign) or inadequate observation of ultrasonographic findings. (e.g., hyperechoic stroma in polycystic ovarian syndrome).

The roles of clinical assessment, human chorionic gonadotropin assays, and ultrasonography in medical abortion practice

The clinical assessment of patients who request early medical abortion includes confirmation of the diagnosis of pregnancy and estimation of gestational age. Accurate gestational dating is essential, because the efficacies of medical abortion regimens decline as pregnancy advances. Whereas medical abortion researchers in the United States have relied on routine ultrasonography for gestational dating, abortion providers experienced with mifepristone and prostaglandin regimens outside the United States have reported high efficacy and safety primarily with clinical dating parameters. Diligent follow-up of patients allows clinicians to confirm that complete abortion has occurred without complications. In cases of uncertain outcome or suspected ectopic pregnancy, transvaginal ultrasonography and beta-human chorionic gonadotropin assays can assist in prompt diagnosis and management. As medical abortion with mifepristone and misoprostol becomes more prevalent in the United States, studies will be needed to further evaluate the effects of these modalities on medical abortion outcomes.

Role of pelvic ultrasonography in evaluation of symptomatic first-trimester pregnancy

Early identification of an abnormal pregnancy is important. The diagnosis of ectopic pregnancy before tubal rupture can prevent life-threatening hemorrhage. This article provides a review of the normal development in early pregnancy and correlates this with ultrasound findings, followed by a structured approach to the ultrasound examination. The specific findings in early pregnancy are reviewed, and the predictive value of these findings in identifying either a normal or abnormal intrauterine pregnancy or an ectopic pregnancy are discussed.

Pelvic ultrasonography

Pelvic ultrasonography is a valuable tool for the emergency physician in the evaluation of the wide spectrum of pelvic complaints presenting to the emergency department. The goal of this article is to outline pelvic problems that can be readily identified by the emergency physician using pelvic sonography early in the patient's evaluation. A special emphasis is placed on the sonographic diagnosis of ectopic pregnancy.

Endometrial color flow/image-directed Doppler imaging: negative predictive value for excluding ectopic pregnancy

PURPOSE

Visualization of an intrauterine pregnancy with transvaginal ultrasound virtually excludes an ectopic pregnancy. However, findings that might lower patients' risk for ectopic pregnancy have not been extensively investigated. We prospectively performed transvaginal color flow/image-directed Doppler imaging of the endometrium to determine the predictive value of endometrial blood flow for excluding ectopic pregnancy.

MATERIALS AND METHODS

From April 1994 to August 1995, 211 consecutive women underwent transvaginal ultrasound examination to exclude an ectopic pregnancy. Color flow/image-directed Doppler imaging of the endometrium was performed on each patient. Flow was considered to be present only if a Doppler signal could be obtained with the cursor located completely within the endometrium. All Doppler imaging parameters were optimized for each patient. Resistive indices were obtained if arterial signal was present, and receiver operator characteristic curves were constructed for RI and peak systolic velocity. Findings were correlated with surgical and pathology results.

RESULTS

Of 211 total patients, there were 55 ectopic pregnancies (52 diagnosed for a sensitivity of 95%), 89 incomplete spontaneous abortions, 40 completed spontaneous abortions, and 27 intrauterine pregnancies. Of 55 ectopic pregnancies diagnosed with real time imaging, 9 had areas of endometrial blood flow (6 venous, 3 arterial), and 46 did not. Of the 156 patients that did not have an ectopic pregnancy, 107 had arterial blood flow within the endometrium, and 49 had no flow. Using only cases with arterial signal, the negative predictive value of endometrial blood flow for excluding an ectopic pregnancy was 97% (107/107 + 3). The optimal cutoff values (5% false-positive rate) for peak systolic velocity and refractive index (RI) were 15 cm/s and 0.55.

CONCLUSIONS

Arterial blood flow within the endometrium lowers the risk for ectopic pregnancy even when other findings that might indicate a high risk are present. Venous flow within the endometrium does not exclude an ectopic pregnancy.

The spectrum of first-trimester ultrasound findings

A wide spectrum of sonographic findings can be seen in the first trimester of pregnancy. One must have an appreciation of embryology to recognize normal and abnormal early pregnancy development. In this article we emphasize discriminatory criteria for identification of normal structures, as well as ultrasound findings in threatened abortion, failing pregnancy, multiple gestations, ectopic pregnancy, and trophoblastic disease. Sonoembryology, the identification of embryonic anatomy, is discussed, as are examples of early identification of anomalies.

First-trimester ultrasound: the essentials

A review of first-trimester ultrasound findings is presented. The normal first trimester, including practical embryology and pregnancy dating, is first discussed. Abnormal first-trimester findings, including sonographic evaluation of the failing pregnancy, ectopic pregnancy, gestational trophoblastic disease, and first-trimester cystic hygroma, are then stressed. This report reviews the spectrum of findings encountered by sonographers while evaluating early pregnancy.

Transvaginal sonographic features in diagnosis of ectopic pregnancy

OBJECTIVES

To evaluate the efficacy of pelvic transvaginal sonography (TVS) in patients with clinical presentation of extrauterine pregnancy (EUP) and positive beta-hCG.

METHODS

Three hundred and twenty-one patients with clinical suspicion of EUP were subjected to TVS at Maharaj Nakorn Chiang Mai Hospital. The criteria for entry to the study were (1) clinical suspicion of EUP, with stable hemodynamic condition, (2) correct final diagnosis must be known, (3) serum beta-hCG must be determined, by assay sensitivity of 10 mIU/ml (4) TVS was examined by the same sonographer. Frequencies of each TVS feature in EUP and IUP were determined. Among the patients with positive beta-hCG and empty uterus, the accuracy indices of various TVS features in predicting EUP were calculated.

RESULTS

Patients with measurable beta-hCG were divided into two main groups, namely those with demonstrable typical intrauterine gestational sac (52/201), and those without (149/201). None of the subjects in the first group had EUP. Among the latter group of patients, with empty uterus, TVS signs could be further divided into 3 subgroups: (1) Direct sign, clear evidence of extrauterine gestational sac. This group had positive predictive value 100%, but low sensitivity (26%). (2) Indirect signs of EUP, i.e. adnexal mass and pelvic fluid, especially echogenic fluid. Echogenic fluid, adnexal mass and their combination had positive predictive value for EUP 92.3%, 92.8% and 95.0%, respectively. Complex adnexal mass gave the highest sensitivity (85.7%). (3) No positive sign on TVS, which is very unlikely to be EUP, and was found in only 2.8% of EUP.

CONCLUSIONS

The results of this study indicate that TVS can help to facilitate the diagnosis of EUP in most cases. EUP can be confidently diagnosed by demonstration of adnexal ring, and excluded by visualization of intrauterine sac. Complex adnexal mass and echogenic fluid are extremely helpful in making the diagnosis.

Routine ultrasound surveillance of the pregnant uterus

The routine ultrasound examination of the pregnant uterus is presented in this article. The approach is based on published guidelines, dividing the examination into studies of the first trimester and studies of the second and third trimesters. The discussion emphasizes the standard anatomical views and describes the normal sonographic appearances. The methods of obtaining important measurements are described, and tables are provided to analyze these measurements. A systematic approach to obstetric ultrasound is important in ensuring completeness and in maximizing the detection of fetal abnormality.

Ectopic pregnancy in adolescents: a clinical review for pediatricians

Pediatricians caring for sexually active female adolescents and young adults need to be aware of the history, symptoms, and signs of an ectopic pregnancy. A thorough history and physical examination, including the pelvic examination, as well as specific diagnostic tests such as repeated quantitative hCG measurements, and ultrasonography when indicated, are crucial to proper and early diagnosis of a nonruptured ectopic pregnancy manageable by laparoscopy. The key to early diagnosis is to include ectopic pregnancy in the differential diagnosis in any sexually active female patient who has abnormal vaginal bleeding or abdominal pain. With early diagnosis, close observation, and appropriate management, the outcome is more likely to be favorable, with minimal morbidity and risk of death.

The relative chance of pregnancy following tubal or uterine transfer procedures

In a 7-month study period, a total of 113 pregnancies were generated in 380 women (30%) undergoing transfers in one of four assisted conception procedures: gamete intrafallopian transfer (GIFT), pronuclear stage tubal transfer (PROST), tubal embryo stage transfer (TEST), and in vitro fertilization and embryo transfer (IVF-ET). It was shown that both the pregnancy rate per transfer procedure and the number of pregnancy sacs arising per embryo transferred were significantly higher among the groups having tubal transfer (P less than 0.001). There were no significant differences in the pregnancy or implantation rates among the three groups having tubal transfer procedures when the GIFT results were adjusted for a 72% fertilization rate noted in the combined IVF-ET and PROST groups. Early pregnancy wastage showed a similar pattern among the four groups and, overall, 67% of pregnancies advanced beyond 20 weeks.

Suspected ectopic pregnancy: ultrasound findings and hCG levels assessed by an immunofluorometric assay

One hundred suspected ectopic pregnancies were assessed by ultrasound on the basis of the following criteria: (A) viable intrauterine fetus, intrauterine pregnancy is certain; (B) intrauterine double sac or eccentric ring, intrauterine pregnancy is probable; (C) empty uterus or central ring but no adnexal mass or cul-de-sac fluid, ectopic pregnancy is possible; (D) empty uterus or central ring and an adnexal mass or cul-de-sac fluid, ectopic pregnancy is probable; (E) viable ectopic fetus, ectopic pregnancy is certain. Serum human chorionic gonadotrophin (S-hCG) was detected by an immunofluorometric assay (sensitivity 0.2 i.u./l, cut-off level 10 i.u./l). All the 51 patients in groups A and B had an intrauterine pregnancy. Normal gestational sacs were found also at S-hCG levels of less than 3600 i.u./l, the lowest level being 894 i.u./l. Ectopic pregnancy was confirmed in 29 of the 30 women in groups D and E. In the 19 women categorized into group C serial hCG assay and repeated sonography diagnosed ectopic pregnancy in 12 and miscarriage of an intrauterine pregnancy in the other seven. Ectopic pregnancy was always found when no gestational sac was seen by sonography and the hCG level was greater than 1000 i.u./l.

A sensitive urine pregnancy test as an aid in the diagnosis of ectopic pregnancy

A highly sensitive 2-hour tube test for the detection of human chorionic gonadotropin (hCG) in urine was compared with the more resource-demanding radioimmunoassay for hCG in serum as an aid in the diagnosis of ectopic pregnancy. In a first series of 107 patients with the possibility of ectopic pregnancy, the urine test was positive in 31 patients, including all 15 patients shown to have an ectopic pregnancy. In a second series of 113 consecutive patients with ectopic pregnancy, the highly sensitive test was performed in 94 patients. It was positive in 90 (96%). The median time of amenorrhea at diagnosis was 7 weeks, and only 15 patients suffered a rupture of the fallopian tube. A highly sensitive urinary test for hCG is recommended as a screening method for patients giving even the smallest indication of ectopic pregnancy.