Prediction of ectopic pregnancy in women with a pregnancy of unknown location

Abstract

K E Y W O R D S:

Clinical information does not improve the performance of mathematical models in predicting the outcome of pregnancies of unknown location

“…The corresponding results of these rules on the training and test set are shown in Table 4. Section (c) of Table 4 gives the results for M4 when using its optimal weights of 1, 1, and 4 (6). Note that the test set results for the prediction of EP are very similar for M4 and M5.…”

“…These data were also used to develop logistic regression model M4 and to evaluate serum cancer antigen 125 and creatine kinase in the management of PULs, the results of which were previously published (6,12). A PUL was defined with TVS as there being no signs of either an intra-or an extrauterine pregnancy or retained products of conception in a woman with a positive pregnancy test.…”

“…We have previously published on the use of multicategoric logistic regression models to predict the outcome of PULs and in particular the ectopic pregnancy (EP) group (5)(6)(7). To date, the models developed by our unit have been based on hormonal and/or simple demographic data.…”

“…With this in mind, we incorporated risk factors for EP as well as examination findings and ultrasonographic findings such as site-specific tenderness into the development of the optimal logistic regression model and evaluated its subsequent performance. The performance of this new model, which incorporated clinical variables, was then compared to the most effective model to date in predicting EP in the PUL population, M4 (6).…”

“…To date, the models developed by our unit have been based on hormonal and/or simple demographic data. Logistic regression model M1 was based on the hCG ratio (hCG 48 h/hCG 0 h, i.e., the rate of change in serum hCG over 48 hours), logistic regression model M2 was based on the average progesterone level (the mean of the progesterone level at 0 hours and at 48 hours), logistic regression model M3 was based on the woman's age, and logistic regression model M4 was based on the logarithm of the hCG average ([hCG 0 h þ hCG 48 h]/2), the hCG ratio, and its quadratic effect ([hCG ratio À 1.17] Â [hCG ratio À 1.17]) (5,6). In the first study published on the use of logistic regression models to predict EPs in the PUL population, logistic regression model M1 was the most impressive (5).…”