The use of serum inhibin A and activin A levels in predicting the outcome of 'pregnancies of unknown location'.
BACKGROUND
The aim was to evaluate the role of serum inhibin A and activin A in the prediction of the outcome of women with 'pregnancies of unknown location' (PULs).


METHODS
Serum human chorionic gonadotrophin (hCG), progesterone, inhibin A and activin A levels were measured at 0 and 48 h. Differences in the mean levels and the change in levels over 48 h expressed as a ratio (48/0 h) were examined between the three outcome groups--failing PUL, intrauterine pregnancy (IUP) or ectopic pregnancy. Variables were incorporated into logistic regression models to predict the pregnancy outcomes, which were evaluated using receiver operator characteristic curves.


RESULTS
One hundred and forty-one women were classified as PULs: 67 failing PULs (47.5%), 58 IUPs (41.1%) and 16 ectopic pregnancies (11.4%). Activin A levels were not significantly different between the three outcome groups. Inhibin A levels were significantly lower in failing PULs. The logistic regression model based on serum inhibin levels gave an area under the curve (AUC) of 0.88 for failing PUL, 0.87 for IUP and 0.60 for ectopic pregnancy. The model based on serum activin levels gave an AUC of 0.61 for failing PUL, 0.64 for IUP and 0.51 for ectopic pregnancy, and the model based on serum hCG levels gave an AUC of 0.95 for failing PUL, 0.97 for IUP and 0.67 for ectopic pregnancy.


CONCLUSIONS
Serum activin A levels at 0 and 48 h are not helpful in predicting the outcome of PULs. Although serum inhibin A levels may be of use in the prediction of failing PULs and IUPs in the PUL populations, they do not perform as well as serum hCG levels.
Kirk
Emma
E
Early Pregnancy and Gynaecological Unit, St George's University of London, Cranmer Terrace, London SW17 0RE, UK. ejkirk@hotmail.co.uk
Papageorghiou
Aris T
AT
Van Calster
Ben
B
Condous
George
G
Cowans
Nicholas
N
Van Huffel
Sabine
S
Timmerman
Dirk
D
Spencer
Kevin
K
Bourne
Tom
T
D028341:Activins / Q000097:blood*; D006063:Chorionic Gonadotropin / Q000097:blood; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007265:Inhibins / Q000097:blood*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D011271:Pregnancy, Ectopic / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D011446:Prospective Studies; D014463:Ultrasonography
D006063:Chorionic Gonadotropin; C422405:activin A; C422362:inhibin A; D028341:Activins; D007265:Inhibins