title: β-hCG resolution times during expectant management of tubal ectopic pregnancies.
abstract: BACKGROUND
  A subset of women with a tubal ectopic pregnancy can be safely managed expectantly. Expectant management involves a degree of disruption with hospital visits to determine serum β-hCG (β-human chorionic gonadotrophin) concentration until the pregnancy test becomes negative and expectant management is considered complete. The length of time required for the pregnancy test to become negative and the parameters that influence this interval have not been described. Information on the likely length of follow up would be useful for women considering expectant management of their tubal ectopic pregnancy.
  
  
  METHODS
  This was a retrospective study at a tertiary referral center in an inner city London Hospital. We included women who were diagnosed with a tubal ectopic pregnancy by transvaginal ultrasound between March 2009 and March 2014. During the study period 474 women were diagnosed with a tubal ectopic pregnancy and 256 (54 %) of them fulfilled our management criteria for expectant management. A total of 158 (33 %) women had successful expectant management and in those cases we recorded the diameter of the ectopic pregnancy (mm), the maximum serum β-hCG (IU/L) and levels during follow up until resolution as well as the interval to resolution (days).
  
  
  RESULTS
  The median interval from maximum serum β-hCG concentration to resolution was 18.0 days (IQR 11.0-28.0). The maximum serum β-hCG concentration and the rate of decline of β-hCG were independently associated with the length of follow up. Women's age and size of ectopic pregnancy did not have significant effects on the length of follow up.
  
  
  CONCLUSIONS
  Women undergoing expectant management of ectopic pregnancy can be informed that the likely length of follow up is under 3 weeks and that it positively correlates with initial β-hCG level at the time of diagnosis.
authors.affiliation: Institute of Women's Health, University College London, London, UK. d.mavrelos@ucl.ac.uk.
authors.forename: D
authors.initials: D
authors.lastname: Mavrelos
authors.affiliation: Gynaecological Diagnostic and Outpatient Treatment Unit, University College London Hospital, Lower Ground Floor, Elizabeth Garrett Anderson Wing, 250 Euston Road, London, NW1 6BU, UK. maria.memtsa@doctors.net.uk.
authors.forename: M
authors.initials: M
authors.lastname: Memtsa
authors.affiliation: University Hospital, Vienna, Austria. samir.helmy@meduniwien.ac.at.
authors.forename: S
authors.initials: S
authors.lastname: Helmy
authors.affiliation: Gynaecological Diagnostic and Outpatient Treatment Unit, University College London Hospital, Lower Ground Floor, Elizabeth Garrett Anderson Wing, 250 Euston Road, London, NW1 6BU, UK. gderd76@yahoo.com.
authors.forename: G
authors.initials: G
authors.lastname: Derdelis
authors.affiliation: Institute of Women's Health, University College London, London, UK. e.jauniaux@ucl.ac.uk.
authors.forename: E
authors.initials: E
authors.lastname: Jauniaux
authors.affiliation: Gynaecological Diagnostic and Outpatient Treatment Unit, University College London Hospital, Lower Ground Floor, Elizabeth Garrett Anderson Wing, 250 Euston Road, London, NW1 6BU, UK. davor.jurkovic@nhs.net.
authors.forename: D
authors.initials: D
authors.lastname: Jurkovic
mesh_terms: D000328:Adult; D000367:Age Factors; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D019468:Disease Management; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008131:London; D008991:Monitoring, Physiologic / Q000379:methods; D011247:Pregnancy; D011258:Pregnancy Tests / Q000379:methods; D011274:Pregnancy, Tubal / Q000097:blood / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D013997:Time Factors; D014463:Ultrasonography
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human