A healthy pregnancy begins with a fertilized egg implanting within the uterus. However, sometimes a fertilized egg implants outside of the uterus, a condition known as an ectopic pregnancy. This serious medical condition requires prompt medical attention.
What is an Ectopic Pregnancy?
An ectopic pregnancy occurs when a fertilized egg attaches itself in a location other than the main cavity of the uterus. While an ectopic pregnancy can implant in various locations, it most commonly occurs in a fallopian tube, accounting for approximately 95% of cases. Within the fallopian tube, the ampullary region is the most frequent site of implantation, making up about 80% of tubal pregnancies. Other, less common sites for ectopic implantation include the ovary, cervix, or abdominal cavity. The lack of adequate space and blood supply in these sites means the fertilized egg cannot develop properly, posing health risks to the pregnant individual.
How Often Do Ectopic Pregnancies Occur?
Ectopic pregnancies occur in approximately 1% to 2% of all pregnancies in the United States. In the United Kingdom, about 1 in every 90 pregnancies is ectopic, totaling around 11,000 cases annually. Historically, the incidence has shown an increasing trend; for instance, in California, the age-adjusted incidence rose from 15.2 per 1,000 pregnancies in 2010 to 16.4 per 1,000 in 2019. The overall age-adjusted incidence across all women in a large California healthcare system from 2010 to 2019 was 15.8 per 1,000 pregnancies. This increase has been partly attributed to improved detection methods and a rise in pelvic inflammatory disease.
Factors That Increase Risk
Several factors can increase an individual’s likelihood of experiencing an ectopic pregnancy:
A prior ectopic pregnancy, increasing the chance of recurrence by about 10%.
Damage to the fallopian tubes, often caused by inflammation or infection, such as pelvic inflammatory disease (PID) from sexually transmitted infections like gonorrhea or chlamydia, also elevates risk.
Previous surgeries on the fallopian tubes, including unsuccessful sterilization procedures, can contribute to the risk.
Fertility treatments, such as in vitro fertilization (IVF), are also associated with a higher incidence of ectopic pregnancy, with rates around 4%.
While rare, becoming pregnant while using an intrauterine device (IUD) increases the likelihood that the pregnancy will be ectopic.
Additionally, smoking before conception can damage the cilia in the fallopian tubes, tiny hair-like structures that help move the egg, thereby increasing ectopic pregnancy risk.
Signs to Look For
The signs and symptoms of an ectopic pregnancy can vary and may not always be immediately apparent, developing between the 4th and 12th week of pregnancy. Common indicators include:
Abdominal or pelvic pain, often on one side of the lower abdomen.
Vaginal bleeding or a brown, watery discharge, different from a normal menstrual period, can also be a symptom.
Shoulder tip pain, an unusual discomfort where the shoulder meets the arm, which can signal internal bleeding irritating the diaphragm.
Dizziness or fainting.
Feeling sick or looking very pale are more severe signs that may indicate a ruptured fallopian tube, which requires immediate medical attention.
Confirmation and Treatment
Confirming an ectopic pregnancy typically involves a combination of diagnostic methods. A pregnancy test to measure human chorionic gonadotropin (hCG) levels is usually performed, and serial measurements may be taken to monitor changes. A pelvic exam may also be part of the assessment.
Transvaginal ultrasound is a primary tool for visualizing the location of the gestational sac and is crucial for diagnosis.
Once an ectopic pregnancy is confirmed, treatment options depend on the individual’s stability and the stage of the pregnancy. Medical management with methotrexate, a medication that stops cell growth, is often used for early, stable cases without signs of rupture. Surgical intervention, such as laparoscopy or, in more severe cases, laparotomy, is performed to remove the ectopic tissue, especially if the fallopian tube has ruptured or the patient is unstable. The goal of treatment is to safely remove the pregnancy while aiming to preserve fertility when possible.