Evaluation of a New Model for Human Chorionic Gonadotropin Rise in Pregnancies of Unknown Viability

Abstract

The proposed human chorionic gonadotropin threshold model optimizes the balance between identifying viable intrauterine pregnancies and minimizing rates of misdiagnosis of nonviable pregnancies.

Evaluation of a New Model for Human Chorionic Gonadotropin Rise in Pregnancies of Unknown Viability

“…We appreciate the efforts of Bollig et al 1 to develop a new threshold model to identify normal early intrauterine pregnancies while minimizing the misdiagnosis of ectopic pregnancies and early pregnancy losses. However, we challenge the use of the terms “viable” and “viability” in this context and aim to highlight the potentially harmful effects of inappropriate use of these terms.…”

“…Smith and Whelan for highlighting the importance of appropriate use of the term "viability," and we appreciate the opportunity to discuss the use of this term in our recent publication in the July 2023 issue. 1 The purpose of our study was to develop a strong prediction rule for early pregnancy outcome when immediate clinical management and counseling relies only on human chorionic gonadotropin (hCG) levels and incorrect management can be devasting. 1 As described by Smith and Whelan, the American College of Obstetricians and Gynecologists (ACOG) recently published guidance on use of the term "viability" in medical practice, stating that, although, ".there is no single formally recognized clinical definition of 'viability,'" one of two uses is to address, ".whether a pregnancy is expected to continue developing normally."…”

In Reply:

“…Smith and Whelan for highlighting the importance of appropriate use of the term “viability,” and we appreciate the opportunity to discuss the use of this term in our recent publication in the July 2023 issue. 1…”

“…The purpose of our study was to develop a strong prediction rule for early pregnancy outcome when immediate clinical management and counseling relies only on human chorionic gonadotropin (hCG) levels and incorrect management can be devasting. 1 As described by Smith and Whelan, the American College of Obstetricians and Gynecologists (ACOG) recently published guidance on use of the term “viability” in medical practice, stating that, although, “…there is no single formally recognized clinical definition of ‘viability,’” one of two uses is to address, “…whether a pregnancy is expected to continue developing normally.” 2 In line with this use of the term, in our study we used a definition of “viability” that needed to be inclusive of features on ultrasonography that are highly positively associated with an ongoing pregnancy and eventual live birth to allow for the best prediction that our model would discriminate pregnancies with continued normal development from those with abnormal progression (pregnancy losses and ectopic pregnancies). Our use of the term “viability” in our article also encompassed patients with “pregnanc(ies) resulting in a live birth,” because some patients included in our study presented for early hCG level measurement but had no further imaging until presentation for delivery.…”

“…We agree with ACOG that this term has many possible interpretations and should not be used inappropriately by policymakers or clinicians to withhold abortion services or other essential pregnancy care. As carefully and specifically stated in our study, our “…model should not serve as evidence to delay care to women with undesired pregnancies seeking abortion,” and, “…if a pregnancy is not desired…treatment should not be withheld while waiting for diagnostic clarity.” 1 In short, for the purposes of our predictive model, the term “viability” should not be used for any interpretation other than its association with an ongoing pregnancy and eventual live birth.…”