Ectopic pregnancy: how many weeks can it occur?

Pregnancy dating starts from the first day of the last menstrual period, while fertilisation happens later. In an ectopic pregnancy, the pregnancy is outside the main cavity of the uterus, most often in a fallopian tube. A pregnancy test may be positive before an ultrasound can show where it is located. A repeat blood test and scan may be needed when the findings are unclear. A history of pelvic inflammatory disease can affect the fallopian tubes and is worth mentioning to the clinician.

Contact a maternity or gynaecology service if you have a positive pregnancy test with one-sided pelvic discomfort, bleeding, or uncertainty about dates. The assessment may include serial pregnancy hormone tests and a transvaginal ultrasound. Until the location is confirmed, follow the review plan closely and keep the contact details for the service available.

Seek emergency help for severe or worsening abdominal or pelvic pain, shoulder-tip pain, fainting, marked dizziness, or heavy vaginal bleeding. These symptoms can signal internal bleeding, even if the pregnancy has been dated only approximately. Do not drive yourself if you feel faint or unwell.

Ask which week is being used for dating, whether the pregnancy location is visible, when your next blood test or scan is due, and which symptoms should prompt immediate assessment.