<prompt> Which of the following would be most likely causing methotrexate therapy failure in ectopic pregnancy treatment.Multiparous womanEctopic size 2.5 cmPrevious history of ectopic pregnancySerum β hcG level of 9000 mIU mL.  <response>: With methotrexate therapy, serum β-hcG levels should decline. If β-hcG rises then it is failure of medical management. 