The Mayo Clinic says normal pregnancies begin when a fertilized egg attaches to the uterine lining. With an ectopic pregnancy, the fertilized egg implants somewhere else. These are rare, with 20 in every 1000 pregnancies being ectopic.
According to Planned Parenthood, “ectopic” means out of place. In most ectopic pregnancies, the egg attaches to the fallopian tube, which is why they are also called tubal pregnancies. Rarely, they can implant in other places like the cervix, ovary or abdomen.
These areas cannot sustain a pregnancy. KidsHealth.org says as the fetus grows, it will eventually burst the organ containing it. This can cause severe bleeding and endanger the mother's life.
The National Institutes of Health (NIH) says an ectopic pregnancy is often caused by a condition that blocks or slows the movement of a fertilized egg through the fallopian tube to the uterus.
Planned Parenthood lists risk factors for ectopic pregnancy as a history of pelvic inflammatory disease (PID) or endometriosis:
Being age 30 or older
Having a previous ectopic pregnancy or abdominal
Fallopian tube or pelvic surgery
Having a fertilized egg placed in a fallopian tube during an infertility procedure
Another thing to note is that if pregnancy occurs when using birth control pills, an intrauterine device (IUD) or after tubal ligation, the pregnancy is more likely to be ectopic.
KidsHealth.org says ectopic pregnancies can be difficult to diagnose because early symptoms often mirror those of a normal pregnancy. These can include missed periods, breast tenderness, nausea, vomiting or frequent urination.
The Mayo Clinic warns that ectopic pregnancies can't continue as normal. The first signs ectopic pregnancies are progressing often include light vaginal bleeding, lower abdominal pain and cramping on one side of the pelvis. If the fallopian tube ruptures, symptoms may include sharp, stabbing pain in the pelvis, abdomen or even the shoulder and neck, dizziness and lightheadedness.
Ectopic pregnancy is treated with medication or surgery. With an early ectopic pregnancy, an injection of methotrexate can be used to stop the embryo’s growth.