Women's HealthPending review

Ectopic pregnancy

A fertilised ovum implants outside the uterine cavity, most often in the fallopian tube, which cannot safely expand to accommodate a growing pregnancy and eventually ruptures through its own vessels, a time-critical surgical emergency.

First principles

The tube is anatomically the wrong place to implant

The uterine cavity has a thick muscular wall and a purpose-built decidua to accommodate trophoblastic invasion. The fallopian tube has a thin muscular coat and a mucosal lining never designed to support a placenta. When the blastocyst implants in the tube (usually the ampulla), the trophoblast still invades exactly as it would in the uterus, but the surrounding tissue cannot stretch or vascularise safely to keep pace.

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Educational content pending clinical review. Not medical advice.