What is an ectopic pregnancy?

Q: My friend had an ectopic pregnancy recently. What is this, and does it affect future pregnancies?

A: An ectopic, or "tubal," pregnancy occurs when a fertilized egg becomes implanted in an area other than the uterus. Ectopics occur in one of the two fallopian tubes 95 percent of the time; these cases usually are due to scarring from an earlier pelvic infection or inflammation. The remaining 5 percent occur on an ovary or, rarely, elsewhere in the abdominal cavity.

Ectopic pregnancies are not viable and can be life-threatening to the mother if they rupture. Symptoms may include a missed period, pelvic or abdominal pain, bleeding or spotting; a diagnosis typically is made by vaginal exam or ultrasound. Depending on the size and location of the ectopic, it may be treated with a chemical that dissolves the fertilized egg; or surgery may be necessary to remove the egg and sometimes the fallopian tube itself.

Since scarring in one fallopian tube may make scarring in the other tube more likely, doctors are extra-vigilant about watching subsequent pregnancies via ultrasound to be sure they are developing safely.