Hum. Reprod. Advance Access published online on June 23, 2009
Human Reproduction, doi:10.1093/humrep/dep066
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
The use of serum inhibin A and activin A levels in predicting the outcome of ‘pregnancies of unknown location’
1 Early Pregnancy and Gynaecological Unit, St George's University of London, Cranmer Terrace, London SW17 0RE, UK 2 Fetal Medicine Unit, St George's University of London, London, UK 3 Department of Electrical Engineering (ESAT-SISTA), K.U. Leuven, Leuven, Belgium 4 Early Pregnancy and Advanced Endosurgery Unit, Nepean Hospital, Nepean Clinical School, University of Sydney, Sydney, Australia 5 Department of Clinical Biochemistry, King George Hospital, Goodmayes, Essex, UK 6 Department of Obstetrics and Gynaecology, University Hospital Gasthuisberg, K.U. Leuven, Leuven, Belgium 7 Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0HS, UK
8 Correspondence address. E-mail: ejkirk{at}hotmail.co.uk
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.
Key words: activin A/inhibin A/pregnancy of unknown location/human chorionic gonadotrophin/ectopic pregnancy
Submitted on September 28, 2008; resubmitted on December 5, 2008; accepted on December 18, 2008.