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Discriminatory zone ultrasound pregnancy dating


The evolution of the diagnosis and management of women with an early pregnancy loss has been a success story. The mortality from ectopic pregnancy has objectively been decreased in the past few decades. However, modern management has resulted in a new set of issues. Over-interpretation of a single ultrasound, misunderstanding of the utility of serial hCG values and inappropriate use of methotrexate can result in iatrogenic complications.

Modern management has successfully improved the diagnosis of ectopic pregnancy before rupture; it should now also focus on ensuring that an intrauterine pregnancy is not interrupted as a result Discriminatory zone ultrasound pregnancy dating diagnosis and treatment. This article reviews some of the pitfalls of the modern management of early pregnancy failure and introduces a series of articles on the subject.

In little more than a generation, the diagnosis and management of a woman with an early pregnancy failure have changed dramatically. Treatment has moved out of the hospital and into outpatient clinics, away from the surgical suite and toward medical or expectant management. Cases of management of shock and catastrophic bleeding are rare, while diagnosis and treatment before symptoms are experienced has become common.

Technological advances and consideration of the risks associated with ectopic pregnancy have resulted in prompt, safe care 1. Modern management has, however, resulted in new pitfalls and dilemmas. In this series of articles, we "Discriminatory zone ultrasound pregnancy dating" explore how modern management of early pregnancy failure has increased iatrogenic complications, concomitantly to reducing morbidity and mortality associated with ectopic rupture.

A woman who presents with vaginal bleeding and pain is at risk for early pregnancy failure. By far, the most common complication is that of miscarriage. A ruptured EP presents Discriminatory zone ultrasound pregnancy dating intraperitoneal hemorrhage and should be treated emergently. Currently most patients present before rupture and with non-specific symptoms, raising new questions: The most recent mortality data available estimated between and demonstrates that mortality resulting from EP has declined significantly to a Discriminatory zone ultrasound pregnancy dating US national average of 0.

This translates to an average of 21 deaths from EP annually 2. There has also been a dramatic change from open surgical procedures, transitioning through laparoscopic procedures, now shifted towards a predominance of medical management or even expectant management.

These historical trends are well demonstrated in the article by Dr. Today, women not initially diagnosed with ultrasound are followed with algorithms involving serial hCG values, follow up ultrasounds, and, at times, laparoscopy or uterine curettage. As more women undergo such surveillance, it should be recognized that these algorithms and decision aids are not without error 4.

An error can result in false reassurance that a woman does not have an ectopic pregnancy, or conversely, interruption of a desired intrauterine pregnancy IUP during diagnosis and management. One common error resulting in misdiagnosis is the reliance on ultrasound findings without full consideration of the clinical circumstances. Ultrasound is a very accurate diagnostic test, however, ultrasound does have quantifiable false positive and false negative rates 56.

Importantly, because such a high number of women undergo ultrasound, even when the rate of misdiagnosis with ultrasound is low, Discriminatory zone ultrasound pregnancy dating number of errors can become clinically important. The prevalence of ultrasound in early pregnancy increases the total accumulation of error in the scans.

Ectopic pregnancy occurs at a...

An important adjuvant to ultrasound is the use of serum hCG concentrations. While hCG values can inform clinical management, they can also be misinterpreted. A single measurement of hCG is neither diagnostic of pregnancy location nor viability. A single hCG value, however, can be used as a surrogate marker for gestation using the concept of an hCG discriminatory zone.

Discriminatory zone ultrasound pregnancy dating reason a pregnancy is not visualized is that the ultrasound was performed too early and the gestational sac has not yet developed. To address this issue, we use the concept of a discriminatory zone 12 The discriminatory zone is the hCG value at which, if no IUP is visualized with ultrasound, one can be confident that a healthy singleton intrauterine gestation is not present.

However, this concept is not always applied correctly. If no intrauterine gestation is visualized when the hCG is above the discriminatory zone, it Discriminatory zone ultrasound pregnancy dating not diagnose an ectopic pregnancy, but only suggests the pregnancy is not viable, i.

The hCG discriminatory zone is not the lowest level at which an Discriminatory zone ultrasound pregnancy dating pregnancy can be detected with ultrasound. A clinical practice should use a high discriminatory zone to reduce the error of missing an intrauterine pregnancy.

Technological advances in ultrasound resolution should not result in a use of a lower discriminatory zone, but should only improve the accuracy of identifying early pregnancy failure. A normal gestational sac should be seen at about 5 weeks and 5 days from last normal menstrual period 1415regardless of whether the pregnancy is a singleton or a multiple gestation.

The hCG discriminatory zone itself is a surrogate marker for gestational age only. Thus, gestational age should affect clinical decision-making more than a single value of hCG.

The discriminatory zone of β-HCG...

When the gestation is not seen in the uterus or in the adnexa, a woman is in a transient state called a pregnancy of unknown location PUL. Management of a PUL can be a clinical conundrum, as one needs to balance the morbidity of a failed gestation with the morbidity of treatment or Discriminatory zone ultrasound pregnancy dating procedures needed to make a diagnosis The issue of diagnosing and classifying a PUL is also a relatively modern problem.

A PUL is not a diagnosis, but instead a transient state.

hCG discriminatory zone Sonography of...

A consensus of the nomenclature for the outcome of women initially noted to have a PUL has been published However, the need to diagnose the location of a pregnancy is still debated. In the accompanying articles, the two sides of the debate are presented. Reid and Condous have taken the position that the location of an intrauterine pregnancy need not be identified in all cases for reasons of cost and time savings Chung reviews the rationale in support of a definitive diagnosis of the location of a pregnancy The rationale is to minimize incorrect diagnosis, to provide appropriate prognostic information for future pregnancies, and to limit over-treatment of women with a chemotherapeutic agent that is teratogenic and has side effects.

As noted by Dr. It should also be noted that Discriminatory zone ultrasound pregnancy dating decision analysis attempting to quantify the number of visits necessary to treat a woman with a nonviable PUL demonstrates that the only advantage to Discriminatory zone ultrasound pregnancy dating methotrexate treatment is reduced clinician time. There are no cost savings or reduction of side effects, and there is an increase in number of visits required by the patient Because all diagnostic tests Discriminatory zone ultrasound pregnancy dating false positive and false negative rates, as a large number of women undergo surveillance, the number of diagnostic errors will increase.

An ectopic pregnancy is an...

This is particularly true when surveillance is started early in a gestation and when women are asymptomatic. Real world examples of diagnostic errors resulting from early intervention perhaps too early are demonstrated by Bottomley et al 24 and Morse et al 4. Bottomley et al demonstrated that when ultrasound is performed after 49 days of gestation, it reduces the number of inconclusive scans without an associated increase in morbidity from missed ectopic pregnancies, thus decreasing false diagnoses In other words, there is harm in performing an ultrasound in a woman without symptoms when one does not expect to see an intrauterine gestation.

A clinician Discriminatory zone ultrasound pregnancy dating be misled by non definitive and false findings, leading to more tests and potential diagnostic errors.

This begs the question: Unnecessary intervention will be initiated in a number of women due to over-surveillance. An additional iatrogenic problem introduced by modern management of early pregnancy failure is inappropriate use of medical management. The use of methotrexate to treat ectopic pregnancy was first cited in Since then, the use of methotrexate has revolutionized the treatment of EP.

As medical management has become routine, new questions have arisen. For example, what is the optimal treatment regimen? Do all women need to be screened and monitored for serum measures of toxicity? Should the use of methotrexate be expanded to women with a presumed EP but not definitively diagnosed?

It seems that some clinicians Discriminatory zone ultrasound pregnancy dating sacrificing therapeutic results for ease of administration.

One "Discriminatory zone ultrasound pregnancy dating" explanation is because each individual clinician treats only a few patients a year, it is easy to attribute an occasional failure as anticipated, rather than recognize that a more effective treatment regimen will reduce the failure rate. A two-dose protocol was designed to provide a second dose of methotrexate at an earlier time point, without an increase in visits, to minimize this gap in success rates between single-dose and multi-dose The selection of appropriate candidates for medical management is well published in guidelines, including the American Society for Reproductive Medicine 26 and the American College of Obstetricians and Gynecologists It has recently been suggested that because the use of methotrexate is no longer experimental, and the vast majority of women who are treated are healthy, it is neither necessary, nor cost effective to routinely screen and monitor all women for evidence of elevated liver enzymes given that the vast majority return to normal without clinical consequence Perhaps a larger debate is if methotrexate should be used when the diagnosis is presumed and not confirmed.

There is real Discriminatory zone ultrasound pregnancy dating in administering a chemotherapeutic agent, known to be abortifacient and teratogenic, if a viable pregnancy has not been ruled out.

Improper administration of methotrexate to a woman who has an intrauterine pregnancy is more common than may be suspected The prevalence is "Discriminatory zone ultrasound pregnancy dating" increased because of the increase in use of methotrexate in general, and the expanded use to women with a pregnancy of unknown location. Because methotrexate is so easy to administer, it is often given to women when an ectopic pregnancy is suspected or when there is simply no Discriminatory zone ultrasound pregnancy dating of an intrauterine pregnancy based on ultrasound.

Inappropriate use of methotrexate is most common in two clinical scenarios. The first is that methotrexate is administered on first presentation for care when hCG values are relatively Discriminatory zone ultrasound pregnancy dating or above a defined discriminatory zone. There is almost no reason to give methotrexate on first encounter with a patient. If a patient is symptomatic with severe pain or signs of rupture, a surgical approach is indicated and methotrexate is contraindicated.

If the patient is clinically stable and Discriminatory zone ultrasound pregnancy dating ultrasound is not definitive, repeat ultrasound can provide confirmation of diagnosis. Moreover, a repeat hCG value will provide evidence of progression, resolution or plateau. If no adnexal mass is Discriminatory zone ultrasound pregnancy dating by ultrasound, it is unlikely that an EP if present has started to hemorrhage.

Thus, it is unlikely to rupture before scheduled follow up. Administration of methotrexate because of its convenience can result in disastrous complications.

There are numerous reports that have later documented intrauterine pregnancy after a woman has been treated with methotrexate.


Methotrexate administration often results in miscarriage, but in some instances women treated for a suspected ectopic pregnancy have been diagnosed with an ongoing intrauterine pregnancy. In some instances, live born infants with malformations have been delivered.

Wrongful treatment with methotrexate has become a common reason for medical liability. Awards for cases of children born with malformations due to Discriminatory zone ultrasound pregnancy dating have been in excess of 20 million dollars.

It is understandable that such inappropriate administration of methotrexate is not often reported in the medical literature. Despite likely underreporting, there are numerous case reports of methotrexate resulting in craniofacial, skeletal, cardiovascular Discriminatory zone ultrasound pregnancy dating gastrointestinal anomalies 32 - Other documented abnormalities Discriminatory zone ultrasound pregnancy dating included intrauterine growth retardation, hypertelorism, facial nerve palsy, scoliosis, and cardiovascular abnormalities 32 - An additional clinical conundrum is the management of a woman with a first trimester pregnancy of uncertain viability.

When a miscarriage is suspected and ectopic pregnancy is not suspectedthere should be no rush to diagnosis and treatment. gestational dating, and limited fetal biometry.

The discriminatory zone is the...

Image Acquisition. Ultrasound images in early pregnancy can be acquired in two ways, transabdominally and transvaginally . For TVUS, the discriminatory zone is generally accepted as between. Often used in the evaluation of early pregnancy, the hCG discriminatory zone is based on the assumption that a serum ß-hCG level exceeding 1,–2, Figure 1 Transvaginal ultrasound image of a gestational sac consistent with The “discriminatory zone” of human chorionic gonadotrophin "Discriminatory zone ultrasound pregnancy dating" is that When exact pregnancy dating is available, an intrauterine pregnancy.

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