The Yolk Stalk Sign

Objective. The purpose of this study was to assess the positive predictive value for confirming early embryonic death in the clinical sonographic scenario wherein an embryo is identified without a visible heartbeat; the embryonic crown‐rump length (CRL) is 5 mm or less; and the embryo is not immediately adjacent to the yolk sac. Methods. A retrospective study of 882 first‐trimester sonograms was performed among women who had an intrauterine pregnancy of uncertain viability based on 1 or more sonographic findings (eg, no visible heartbeat in an embryo with a CRL of ≤5 mm). Eight hundred six cases met the inclusion criteria. Results. Among the cohort of 806 cases, 520 (64.5%) had an identifiable embryo. One hundred fifty‐nine of these embryos had no demonstrable heartbeat and a CRL of 5 mm or less. The CRLs of these embryos ranged from 1.7 to 5.4 mm. This cohort's sonograms were reviewed to determine whether there was a separation between the embryo and yolk sac. Twenty‐one cases were discovered. Recall that as a retrospective study, no specific effort was made to show this finding. Thus, a computation of the sensitivity of this finding would result in an underestimate of indeterminate magnitude. All of these cases were subsequently proven to be failed pregnancies. Conclusions. The positive predictive value of the “yolk stalk sign” in determining early pregnancy failure for an embryo with a CRL of 5 mm or less and no visible heartbeat was 100% in this cohort.     

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.     

Doppler examination of uteroplacental circulation in early pregnancy: Can it predict adverse outcome?

PURPOSE: To determine whether spectral Doppler measurements obtained from bilateral uterine, arcuate, radial, and spiral arteries in early gestation correlate with adverse pregnancy outcome. METHODS: One hundred five pregnant women underwent transvaginal Doppler sonographic examination of uteroplacental circulation at 6-12 weeks' gestation. Resistance index (RI) and pulsatility index (PI) of bilateral uterine, arcuate, radial, and spiral arteries were measured. Diameters of gestational sac (GS) and yolk sac, crown-rump length (CRL), GS-CRL difference, and GS/CRL ratio were also recorded. Correlation was made with pregnancy outcome. RESULTS: Sixteen women developed adverse pregnancy outcome. In these women, right uterine artery PI and RI were significantly higher than in women with normal obstetrical outcome. Spiral artery PI and RI values were also higher, but the difference was not statistically significant. GS-CRL difference, GS/CRL ratio, and yolk sac diameters were significantly lower in this group. CONCLUSION: Transvaginal Doppler examination can detect hemodynamic changes in uteroplacental circulation associated with subsequent adverse pregnancy outcome.     

The chorionic bump in an ectopic pregnancy

The chorionic bump, an irregular, convex bulge of the choriodecidual surface into the gestational sac (GS), is a recently described, uncommon abnormality of the 1^st‐trimester GS and is associated with a guarded prognosis for early pregnancy. The case of this 42‐year‐old female demonstrates a previously unreported relationship: a transvaginal sonographic finding of a chorionic bump associated with a spontaneous tubal ectopic pregnancy. This might support the hypothesis that the chorionic bump represents a small hematoma that bulges into the GS. © 2008 Wiley Periodicals, Inc. J Clin Ultrasound, 2009     

"Rule out ectopic": Asking the right questions, getting the right answers

Sonographic evaluation of the pregnant patient suspected of harboring an ectopic pregnancy (EP) helps determine patient management. Although clinicians typically ask sonologists to "rule out" EP in these patients, the sonologist actually must answer 3 questions: (1) Is there an intrauterine pregnancy (IUP)? (2) Is the possibility of normally developing IUP reliably excluded? (3) Are there sonographic findings that identify or increase the likelihood of an EP? Understanding the rationale behind these questions and the sonographic findings that help to answer these questions enables the sonologist to contribute meaningfully to the care of patients with possible EP. Beginning the sonographic examination with a limited transabdominal approach has value. An IUP can be confidently diagnosed by identification of an intradecidual sac exhibiting the double decidual sac sign, yolk sac, or embryo. When the serum beta human chorionic gonadothropin exceeds 2000 mIU/mL, a technically excellent sonographic examination should identify an intradecidual sac potentially representing an IUP. Even without directly visualizing a yolk sac or embryo in the adnexa, the presence of an extraovarian mass or hemoperitoneum strongly predicts the possibility of EP. An intraovarian mass with peripheral hypervascularity is more likely to represent the corpus luteum rather than an intraovarian EP. Cervical EP can be distinguished from the cervical phase of a spontaneous abortion in progress by either demonstrating fetal heart motion or persistence or enlargement of findings on short-interval follow-up. Absence of a myometrial mantle surrounding one edge of an IUP positioned at the fundus is suspicious for an interstitial EP.     

Do early pregnancy ultrasound measurements correlate with fetal nuchal translucency at 11-14 weeks?

OBJECTIVE: To assess whether extremes in nuchal translucency (NT) thickness measurements at 11-14 weeks of gestation are preceded by departures from normal in early ultrasound biometry or embryonic heart rate in euploid fetuses. METHODS: This was a retrospective analysis of data from women with singleton pregnancies examined in early pregnancy between June 2002 and January 2003, who subsequently had a nuchal translucency (NT) scan. The early pregnancy scan was performed transvaginally, and the crown-rump length (CRL), mean gestational sac diameter (GS), mean yolk sac diameter (YS) and embryonic heart rate (HR) were measured where possible. At the second scan CRL and NT were measured. RESULTS: A total of 534 singleton pregnancies were included in the analysis. The mean maternal age was 30 (range, 14-45) years, and 59.4% of the patients were nulliparous. The mean CRL was 11.5 (range, 1.4-30.0) mm at the first scan and 62.8 (range, 42.0-88.0) mm at the second scan. GS, YS and HR measurements were obtained in 87.6%, 72.5% and 72.5% of cases, respectively. No statistically significant correlation was observed between NT and Z-scores of early pregnancy: GS (r = 0.013, P = 0.77), YS (r = 0.039, P = 0.44) or HR (r = 0.016, P = 0.76). GS, YS and HR were not significantly different in fetuses with NT measurements below the 10th percentile or above the 90th percentile (P = 0.24, 0.84 and 0.60, respectively). CONCLUSION: Ultrasound biometry and heart rate measured in early pregnancy are not related to nuchal translucency measurements at 11-14 weeks of gestation in chromosomally normal fetuses.     

Sonographic evaluation of the yolk sac

This pictorial essay aims to inform related clinicians by summarizing the normal and abnormal sonographic findings of the yolk sac in the first trimester of pregnancy. An abnormality in the sonographic appearance of a yolk sac can predict subsequent embryonic death or abnormalities. Therefore, the accurate recognition of normal and abnormal sonographic findings concerning the yolk sac can be used to anticipate the course of pregnancy.     

Ectopic pregnancy

Ectopic pregnancy occurs at a rate of 19.7 cases per 1,000 pregnancies in North America and is a leading cause of maternal mortality in the first trimester. Greater awareness of risk factors and improved technology (biochemical markers and ultrasonography) allow ectopic pregnancy to be identified before the development of life-threatening events. The evaluation may include a combination of determination of urine and serum human chorionic gonadotropin (hCG) levels, serum progesterone levels, ultrasonography, culdocentesis and laparoscopy. Key to the diagnosis is determination of the presence or absence of an intrauterine gestational sac correlated with quantitative serum beta-subunit hCG (beta-hCG) levels. An ectopic pregnancy should be suspected if transvaginal ultrasonography shows no intrauterine gestational sac when the beta-hCG level is higher than 1,500 mlU per mL (1,500 IU per L). If the beta-hCG level plateaus or fails to double in 48 hours and the ultrasound examination fails to identify an intrauterine gestational sac, uterine curettage may determine the presence or absence of chorionic villi. Although past treatment consisted of an open laparotomy and salpingectomy, current laparoscopic techniques for unruptured ectopic pregnancy emphasize tubal preservation. Other treatment options include the use of methotrexate therapy for small, unruptured ectopic pregnancies in hemodynamically stable patients. Expectant management may have a role when beta-hCG levels are low and declining.     

Low-resistance endometrial arterial flow in the exclusion of ectopic pregnancy revisited.

The objective of this study was to evaluate the efficacy of endometrial arterial flow in the exclusion of ectopic pregnancy. From October 1997 to June 1999, 66 women with elevated beta-human chorionic gonadotropin titers and clinical indications of ectopic pregnancy were evaluated by endovaginal sonography. Women with a gestational sac containing an embryo, a yolk sac, or both were excluded from the study. Doppler ultrasonography was performed in the remaining cases when a definite intrauterine pregnancy could not be visualized. In all cases the thermal index was kept to less than 1.0, consistent with as-low-as-reasonably-achievable principles. Trophoblastic flow was defined as a resistive index of less than 0.6 within the endometrium. Statistical analysis was performed using a 2-tailed t test. Twenty women had ectopic pregnancies; 33 had spontaneous pregnancy losses; and 13 had normal intrauterine pregnancies. A total of 29 women had endometrial trophoblastic flow: 11 of 13 with intrauterine pregnancies, 1 of 20 with ectopic pregnancies, and 17 of 33 with spontaneous pregnancy losses. The negative predictive value for the presence of endometrial low-resistance flow for excluding ectopic pregnancy was 97%. The presence of low-resistance arterial endometrial flow can be a useful sign in diagnosing an early intrauterine pregnancy and decreasing the probability that an ectopic pregnancy is present, particularly in patients with otherwise normal ultrasonographic findings.     

The empty amnion: a sign of early pregnancy failure.

Between 6.5 to 10 weeks of gestation, the length of the amniotic cavity is similar to that of the embryo. It follows that by the time an amniotic sac is detectable sonographically, an embryo of equal length should also be visualized. Retrospective review of case records at our institution revealed 15 patients in whom the amnion was visualized in the absence of an embryonic pole during first trimester sonography (endovaginal and transvesical). Indications for sonographic examination included gestational age estimation, discrepant size and dates, or vaginal bleeding. The mean sac diameter for the 15 gestations ranged from 14 to 36 mm, corresponding to gestational ages of 6.1 to 9.5 weeks. Ages based on the last menstrual period ranged from 6.1 to 11 weeks. A yolk sac was identified in all cases in addition to the amniotic sac, but neither an embryo nor cardiac pulsations were observed. In 12 of the 15 cases the size of the gestational sac was greater than 16 mm, such that the absence of an embryo also met an accepted criterion for a failed pregnancy. Follow-up in all cases confirmed early pregnancy failure. In this series the demonstration of an "empty amnion" (visualization of an amnion but no identifiable embryonic pole) was always associated with pregnancy loss. The "empty amnion" sign is helpful as an additional finding confirming early pregnancy failure.     

Diagnosis and management of ectopic pregnancy

Ectopic pregnancy is a high-risk condition that occurs in 1.9 percent of reported pregnancies. The condition is the leading cause of pregnancy-related death in the first trimester. If a woman of reproductive age presents with abdominal pain, vaginal bleeding, syncope, or hypotension, the physician should perform a pregnancy test. If the patient is pregnant, the physician should perform a work-up to detect possible ectopic or ruptured ectopic pregnancy. Prompt ultrasound evaluation is key in diagnosing ectopic pregnancy. Equivocal ultrasound results should be combined with quantitative beta subunit of human chorionic gonadotropin levels. If a patient has a beta subunit of human chorionic gonadotropin level of 1,500 mIU per mL or greater, but the transvaginal ultrasonography does not show an intrauterine gestational sac, ectopic pregnancy should be suspected. Diagnostic uterine curettage may be appropriate in patients who are hemodynamically stable and whose beta subunit of human chorionic gonadotropin levels are not increasing as expected. Appropriate treatment for patients with nonruptured ectopic pregnancy may include expectant management, medical management with methotrexate, or surgery. Expectant management is appropriate only when beta subunit of human chorionic gonadotropin levels are low and declining. Initial levels determine the success of medical treatment. Surgical treatment is appropriate if ruptured ectopic pregnancy is suspected and if the patient is hemodynamically unstable.     

Sonography of pregnancies with first-trimester bleeding and a small intrauterine gestational sac without a demonstrable embryo.

OBJECTIVE: This was a prospective observational cohort study to evaluate the outcome and prognostic criteria of pregnancies with first-trimester bleeding and a gestational sac 相似文献   

Single point biochemical measurement algorithm for early diagnosis of ectopic pregnancy

ObjectivesTubal rupture as a result of an ectopic pregnancy is the leading cause of first trimester maternal mortality. Currently, the diagnosis of ectopic pregnancy depends on transvaginal ultrasound and serial serum measurements of human chorionic gonadotrophin (hCG), which requires follow up. The objective of this study was to examine whether single point measurements at presentation could distinguish between women with ectopic pregnancy, viable pregnancy, and spontaneous miscarriage.Design and methodsSerum total hCG (hCGt), hyperglycosylated hCG (hCGh), free beta subunit of hCG (hCGβ), progesterone (P), and CA-125 were measured by chemiluminescence immunoassay over a 3 month period in 441 women presenting at the emergency room with abdominal pain and a positive pregnancy test. Patient outcomes were followed and confirmed by histology. 65 samples were excluded due to poor sample storage, or lost to follow up.ResultsThe pregnancy outcomes were 175 viable pregnancies, 175 spontaneous miscarriages, and 26 ectopic pregnancies. A serum hCGt < 3736 mIU/mL cut off was 100% sensitive, with 76% specificity, for distinguishing ectopic pregnancy from viable pregnancy; but did not differentiate spontaneous miscarriage. Serum CA125 < 41.98 U/mL produced 100% sensitivity and 43% specificity in distinguishing ectopic pregnancy from spontaneous miscarriage. Sequential application of hCGt and CA-125 cut off followed by ultrasound could detect 100% of ectopic pregnancies with 87% specificity for all intrauterine pregnancies.ConclusionThe combination of serum hCGt < 3736 mIU/mL, followed by CA125 < 41.98 U/mL is a promising algorithm for detecting all ectopic pregnancy at initial presentation.     

Subclassification of Indeterminate Pelvic Ultrasonograms: Stratifying the Risk of Ectopic Pregnancy

Objective : To determine whether the subclassification of indeterminate ultrasound readings can identify patients who are at high, intermediate, or low risk for ectopic pregnancy.
Methods : A retrospective review was made of consecutive ED patients presenting to an urban teaching hospital from August 1991 to December 1994 with abdominal pain and/or vaginal bleeding and a positive β-hCG. Patients who had transvaginal ultrasonograms obtained during the ED visit that were read as indeterminate (no extrauterine findings of ectopic pregnancy and no intrauterine fetal pole or yolk sac) were eligible. Ultrasonograms were subclassified into 5 groups (empty uterus, nonspecific intrauterine fluid, echo-genic debris within endometrial cavity, abnormal sac, normal sac) based on predetermined criteria. Patients were excluded if the final diagnosis could not be definitively determined.
Results : 248 patients were identified. 20 patients were excluded because a final diagnosis could not be determined. Patients with an empty uterus [25/94 = 27% (95% CI 18–36%)] had the highest frequency of ectopic pregnancy. Patients with nonspecific intrauterine fluid collections [4/30 = 13% (95% CI 4–31%)] had the next highest frequency of ectopic pregnancy. Patients with intrauterine echogenic debris [2/39 = 5% (95% CI 1–11%)], abnormal sacs [1/36 = 3% (95% CI 1–9%)], or normal-appearing sacs [0/29 = 0% (95% CI 0 -8%)] had low frequencies of ectopic pregnancy.
Conclusion : Subclassification of indeterminate ultrasound readings identifies patients at high, intermediate, or low risk for ectopic pregnancy and should improve the diagnostic accuracy of ultrasonography in patients at risk for ectopic pregnancy. Key words: ectopic pregnancy; tubal pregnancy; intrauterine pregnancy; ultrasound; diagnosis.     

Ectopic uterine scar pregnancy: A case report

IntroductionImplantation of a gestational sac in a previous Caesarean section scar of the lower uterine segment is a rare form of ectopic pregnancy.Case reportWe report a case of Caesarean scar ectopic pregnancy in a 25-year-old female, diagnosed by ultrasonography and confirmed by magnetic resonance imaging. We present the clinical details, imaging findings, and management of the patient.DiscussionImaging plays an important role in the diagnosis of ectopic pregnancy and ultrasonography is the modality of choice. Ultrasonography features of scar ectopic pregnancy include empty uterus and cervix with normal endometrium and endocervical canal, gestational sac (with embryo and/or yolk sac) in the anterior part of the lower uterine segment in the region of the Caesarean scar with a thin myometrial layer between the bladder wall and gestational sac. Magnetic resonance imaging may be used as an adjunct imaging modality in cases with inconclusive or equivocal sonographic findings. Termination of pregnancy in the first trimester should be considered and treatment options should be individualized as there is no universal agreement on the best or most preferred treatment modality.ConclusionAwareness of specific ultrasound features of scar ectopic pregnancy is crucial for early recognition, correct diagnosis, and initiating prompt management to prevent complications.     

Value of the yolk sac in evaluating early pregnancies

To determine the potential value in identifying a yolk sac in women with suspected ectopic pregnancies, 211 consecutive women who were referred to pelvic sonography with this clinical indication were prospectively studied. Of the 211 patients examined, 104 proved to have a normal intrauterine pregnancy (IUP), 59 had an abnormal (nonviable) IUP, and 48 had a surgically-proven ectopic pregnancy. Considering only intrauterine "sacs" that lacked a visible embryo, a yolk sack was identified in 16 of 26 (62%) normal IUPs, and 3 of 19 (16%) abnormal IUPs, but was not seen in any of six pseudo-gestational sacs in women with ectopic pregnancies. In comparison, a double decidual sac (DDS) finding was thought to be present in 24 of 26 (92%) normal gestational sacs, 12 of 19 (63%) abnormal gestational sacs, and 2 of 6 (33%) pseudogestational sacs. We conclude that in women in whom a living embryo is not identified, demonstration of a yolk sac is reliable evidence for early IUP, and virtually excludes the possibility of an ectopic gestation. Although a yolk sac is less frequently observed than a DDS finding, it is also more specific evidence for an IUP. Careful attention to the yolk sac should permit earlier, more reliable diagnoses of IUP than previously possible.     

Sonographic evaluation of ectopic pregnancy

To assess sonographic findings in the evaluation for ectopic pregnancy, all women referred over a two-year period were prospectively evaluated. The incidence of intrauterine as well as adnexal findings was assessed in an attempt to optimize sonographic evaluation. Visualization of a double decidual sac sign (DDSS) within the uterus provided an accurate means of confirming an intrauterine pregnancy (IUP) prior to embryo visualization. Forty-two of 130 women with IUP were diagnosable only by the DDSS. As a screening test for ectopic pregnancy, sonographic documentation of an IUP provided the only convincing evidence for the absence of an ectopic gestation. Any woman clinically at risk for ectopic pregnancy whose sonogram did not confirm the presence of an intrauterine pregnancy was at relatively high risk (43 per cent) for having an ectopic gestation. Characterization of adnexal findings increased the level of risk for ectopic pregnancy in these women to 70-100 per cent. However, 20 per cent of women with a surgically confirmed ectopic pregnancy had normal adnexal findings.     

Transvaginal ultrasound scanning in early pregnancy and correlation with human chorionic gonadotropin levels.

Pregnancy can be detected early using transvaginal ultrasonography and human chorionic gonadotropin (hCG) measurements. The purpose of this study was to correlate serum hCG levels with transvaginal gestational sac measurements. The mean sac diameter (MSD) and gestational sac diameter (GSD) were calculated as the mean and cube root of the product, respectively, of three sac dimensions taken at right angles. A nonlinear relationship between hCG (natural logarithm) and MSD and GSD was observed. The data were best fitted by a second order polynomial regression model (r2 = 0.98), thereby establishing normal hCG levels for various gestational sac dimensions in early pregnancy.     

Diagnosis of early embryonic demise by endovaginal sonography

To determine the embryonic size at which cardiac activity is always seen in a normal early pregnancy, 398 endovaginal sonograms were evaluated in which the gestational sac contained a yolk sac and/or embryo of less than or equal to 12 mm in crown-rump length (CRL). In the 99 sonograms in which there was a yolk sac but no identifiable embryo, cardiac activity was absent in 75; 58 of these pregnancies progressed normally. Of the 299 sonograms where there was an identifiable embryo with CRL less than or equal to 12 mm, cardiac activity was absent in 31; 29 of these were proven to be failed pregnancies. In two cases the pregnancy progressed normally; the CRL was 2 mm in one case and 4 mm in the other. We conclude that once an embryo is seen by endovaginal sonography, the absence of cardiac activity usually indicates embryonic demise. However, when cardiac activity is absent, one should refrain from definitively diagnosing embryonic demise, based on a single sonogram, if the CRL is less than 5 mm.     

Ultrasound prediction of risk of spontaneous miscarriage in live embryos from assisted conceptions.

OBJECTIVE: An accurate method to predict subsequent miscarriage in live embryos has not yet been established. This pilot study aimed to determine the most discriminatory ultrasound-based model for predicting spontaneous miscarriage after embryonic life was first detected in assisted conceptions. A method for estimating individual risk of miscarriage was developed. METHODS: This was a prospective cross-sectional survey of 322 live singleton embryos in women from an assisted reproductive technology program. Mean sac diameter (MSD), crown-rump length (CRL), embryonic heart rate (EHR), maternal age and gestational age at the first transvaginal scan detecting embryonic life (between 42 and 62 days) were observed. These variables were included in a multivariate model for predicting spontaneous miscarriage occurring prior to 20 weeks. MSD, CRL and MSD minus CRL were assessed in univariate logistic regression analyses. The global diagnostic accuracy of each model was compared directly using receiver-operating characteristics (ROC) curves. RESULTS: The multivariate model demonstrated the best ROC curve for predicting miscarriage (ROC area 0.87; 95% CI, 0.80-0.95). The separate univariate analyses had less diagnostic accuracy. In particular, MSD - CRL had a significantly smaller ROC area (0.65) than did the multivariate model (P < 0.01). CONCLUSIONS: The most discriminatory test for predicting spontaneous miscarriage in live embryos was a multivariate model, which allows estimation of individual risk levels.