Acute and chronic presentation of ectopic pregnancy may be two clinical entities  Kurt T Barnhart, M.D., M.S.C.E., Paolo Rinaudo, M.D., Ph.D., Amy Hummel, B.S., Joseph Pena, M.D., Mary D Sammel, Sc.D., Jesse Chittams, M.S.  Fertility and Sterility  Volume 80, Issue 6, Pages 1345-1351 (December 2003) DOI: 10.1016/j.fertnstert.2003.04.003

FIGURE 1 Two hypothetical distinct natural histories of an ectopic pregnancy (not shown to scale). (A) Patient has a β-hCG concentration that increases well above the discriminatory zone and is often diagnosed with the aid of ultrasound. (B) Patient has a β-hCG concentration that may start to decline before reaching the discriminatory zone, and is often diagnosed without direct visualization on ultrasound using serial β-hCG values. Barnhart. Acute and chronic ectopic pregnancy. Fertil Steril 2003. Fertility and Sterility 2003 80, 1345-1351DOI: (10.1016/j.fertnstert.2003.04.003)