title: The use of serum inhibin A and activin A levels in predicting the outcome of 'pregnancies of unknown location'.
abstract: 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.
authors: Early Pregnancy and Gynaecological Unit, St George's University of London, Cranmer Terrace, London SW17 0RE, UK. ejkirk@hotmail.co.uk
authors: Emma
authors: E
authors: Kirk
authors: Aris T
authors: AT
authors: Papageorghiou
authors: Ben
authors: B
authors: Van Calster
authors: George
authors: G
authors: Condous
authors: Nicholas
authors: N
authors: Cowans
authors: Sabine
authors: S
authors: Van Huffel
authors: Dirk
authors: D
authors: Timmerman
authors: Kevin
authors: K
authors: Spencer
authors: Tom
authors: T
authors: Bourne
mesh_terms: 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
chemical_list: D006063:Chorionic Gonadotropin; C422405:activin A; C422362:inhibin A; D028341:Activins; D007265:Inhibins