What causes an ectopic pregnancy?

Ectopic pregnancy occurs when a fertilized egg implants outside the main cavity of the uterus. The most common location for an ectopic pregnancy is the fallopian tube, where the egg usually travels from the ovary to the uterus.

Causes of ectopic pregnancy include:

1. Damage to the fallopian tubes: Scar tissue or damage to the fallopian tubes, often from previous infections, surgery, or endometriosis, can block or narrow the tubes and prevent the fertilized egg from reaching the uterus.

2. Hormonal imbalances: Hormonal imbalances, such as irregular ovulation or low levels of progesterone, can affect the movement of the fertilized egg through the fallopian tubes.

3. Pelvic inflammatory disease (PID): PID, a bacterial infection of the female reproductive organs, can damage the fallopian tubes and increase the risk of ectopic pregnancy.

4. Congenital abnormalities: Some women have structural abnormalities in the uterus or fallopian tubes that make it difficult for the fertilized egg to implant in the correct location.

5. Assisted reproductive technologies (ART): Ectopic pregnancy is slightly more common in women who have conceived through ART, such as in vitro fertilization (IVF).

It's important to note that not all ectopic pregnancies have a clear identifiable cause, and some cases occur due to a combination of factors.