Typically presents 6-8 weeks after last normal menstrual period, but can present earlier or later.
Risk increases with prior ectopic pregnancy, tubal surgery, history of sexually transmitted infections, smoking, in vitro fertilisation, or if pregnant despite IUD usage.
Classical symptoms and signs are pain, vaginal bleeding, and amenorrhoea. Haemodynamic instability and cervical motion tenderness may indicate rupture or imminent rupture.
If the patient is haemodynamically stable, transvaginal ultrasound is the initial test of choice.
Treatment approaches include expectant, medical (methotrexate), or surgical (salpingectomy, salpingostomy).
Can be complicated by rupture, in which case may present in shock from blood loss and with unusual patterns of referred pain from intraperitoneal blood.
A fertilised ovum implanting and maturing outside of the uterine endometrial cavity, with the most common site being the fallopian tube (97%), followed by the ovary (3.2%) and the abdomen (1.3%).  If undiagnosed or untreated, it may lead to maternal death due to rupture of the implantation site and intraperitoneal haemorrhage. 
William Shippen Jr. Professor of Obstetrics and Gynecology and Epidemiology
Vice Chair for Clinical Research
Director, Women's Health Clinic Research Center
The Perelman School of Medicine
University of Pennsylvania
Associate Chief, Penn Fertility Care
KTB declares that he has no competing interests.
Dr Kurt T. Barnhart would like to gratefully acknowledge Dr Ingrid Granne, Dr Veronica Gomez-Lobo, Dr Sina Haeri, and Dr Mohammad Ezzati, previous contributors to this monograph. IG, VGL, SH, and ME declare that they have no competing interests.
Reproductive Biology Medicine and Biology
AD declares that he has no competing interests.
Consultant in Obstetrics and Gynaecology
West Middlesex University Hospital
JCG declares that she has no competing interests.
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