Abstract
Purpose: To study the value of a single or repeated GnRH agonist stimulation test (GAST)
in predicting outcome in IVF compared to basal ovarian reserve tests.
Methods: A total of 57 women was included. In a cycle prior to the IVF treatment, on day
3, an antral follicle count (AFC) was performed and
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blood taken for basal FSH, inhibin B and E2 measurements, followed by a subcutaneous injection of 100 μg triptorelin for the purpose of the GAST. Twenty-four hours later blood sampling was repeated. All the tests were repeated in a subsequent cycle. From the GAST E2 and inhibin B response were used as test parameters. The outcome measures were poor ovarian response and ongoing pregnancy. Group comparisons were done using the Mann–Whitney or chi-square test. Univariate and multivariate logistic regression was applied to assess which test revealed the highest predictive accuracy as expressed in the area under receiver-operating characteristic curve
(ROCAUC). Clinical value was compared by calculating classical test characteristics for the best logistic models.
Results: All the basal and GAST variables were significantly different in the poor responders (n = 19) compared to normal responders (n = 38). In the univariate analysis on cycle 1 tests the AFC was the best predictor for poor ovarian response, while in cycle 2 the E2 response in the GAST performed best (ROCAUC of 0.91 for both). Multivariate analysis of the basal variables led to the selection of AFC and inhibin B in cycle 1, yielding a ROCAUC of 0.96. Mean E2 response was selected in a multivariate analysis of the repeated GAST variables
(ROCAUC 0.91). At a specificity level of ∼0.90, several logistic models including GAST variables appeared to have a sensitivity (∼0.80), positive predictive value (∼0.82) and false positive rate (∼0.18), comparable to a logistic model containing AFC and inhibin B. None of
the test variables showed a significant relation with ongoing pregnancy.
Conclusions: The GAST has a rather good ability to predict poor response in IVF. However, comparing the predictive accuracy and clinical value of the GAST with a day 3 AFC and inhibin B, it appeared that neither a single nor a repeated GAST performed better. In addition, the predictive ability towards ongoing pregnancy is poor. Therefore, the use of the GAST as a predictor of outcome in IVF should not be advocated.Purpose: To study the value of a single or repeated GnRH agonist stimulation test (GAST)in predicting outcome in IVF compared to basal ovarian reserve tests.
Methods: A total of 57 women was included. In a cycle prior to the IVF treatment, on day
3, an antral follicle count (AFC) was performed and blood taken for basal FSH, inhibin B and E2 measurements, followed by a subcutaneous injection of 100 μg triptorelin for the purpose of the GAST. Twenty-four hours later blood sampling was repeated. All the tests were repeated in a subsequent cycle. From the GAST E2 and inhibin B response were used as test parameters. The outcome measures were poor ovarian response and ongoing pregnancy. Group comparisons were done using the Mann–Whitney or chi-square test. Univariate and multivariate logistic regression was applied to assess which test revealed the highest predictive accuracy as expressed in the area under receiver-operating characteristic curve
(ROCAUC). Clinical value was compared by calculating classical test characteristics for the best logistic models.
Results: All the basal and GAST variables were significantly different in the poor responders (n = 19) compared to normal responders (n = 38). In the univariate analysis on cycle 1 tests the AFC was the best predictor for poor ovarian response, while in cycle 2 the E2 response in the GAST performed best (ROCAUC of 0.91 for both). Multivariate analysis of the basal variables led to the selection of AFC and inhibin B in cycle 1, yielding a ROCAUC of 0.96. Mean E2 response was selected in a multivariate analysis of the repeated GAST variables
(ROCAUC 0.91). At a specificity level of ∼0.90, several logistic models including GAST variables appeared to have a sensitivity (∼0.80), positive predictive value (∼0.82) and false positive rate (∼0.18), comparable to a logistic model containing AFC and inhibin B. None of
the test variables showed a significant relation with ongoing pregnancy.
Conclusions: The GAST has a rather good ability to predict poor response in IVF. However, comparing the predictive accuracy and clinical value of the GAST with a day 3 AFC and inhibin B, it appeared that neither a single nor a repeated GAST performed better. In addition, the predictive ability towards ongoing pregnancy is poor. Therefore, the use of the GAST as a predictor of outcome in IVF should not be advocated.
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