During a normal pregnancy, the embryo — then later, fetus — is positioned inside the uterus, which is designed to nurture and grow it during the gestation process. In some cases, a embryo can attach in areas that are most definitely not designed for a pregnancy — this is called an ectopic pregnancy and can be life-threatening. Let's take a look at what happens during an ectopic pregnancy.
Ectopic pregnancy basics
An ectopic pregnancy is one that isn't located inside the uterus, Dr. Yves-Richard Dole, an OB-GYN at Mercy Medical Center in Baltimore, Maryland, tells SheKnows, adding that around 98 percent tend to be located in a fallopian tube.
"Commonly they are in the fallopian tube but they can be in other places," he says. "They have also been found on the ovary and in the abdomen. A pregnancy needs a surface with a good blood supply to establish itself. Pregnancies have even been noted to have grown on the liver."
Why an ectopic pregnancy happens
Ectopic pregnancies can happen to anyone, Dr. G. Thomas Ruiz, the lead OB-GYN at MemorialCare Orange Coast Medical Center in Fountain Valley, California, tells SheKnows — meaning that it's not something you can be genetically predisposed to.
However, Ruiz notes that there are a few factors that may make you more likely to experience an ectopic pregnancy. A history of previous pelvic infection, the presence of an IUD, history of previous pelvic surgery and, most important, a history of a previous ectopic pregnancy all increase your odds, he explains, adding that cigarette-smoking can also increase your odds of having an ectopic pregnancy as well.
Still, they're overall pretty rare occurrences, only occurring in around 2 percent of all pregnancies according to a study published in the journal Ultrasonography.
Diagnosing an ectopic pregnancy
A sonogram is the easiest way to diagnose an ectopic pregnancy, says Ruiz, especially when combined with blood tests. While we can't imagine going through a pregnancy without at least one sonogram, it's still a relatively new technology and wasn't a commonly used tool in prenatal care until the late '80s.
Even now, different obstetric practices have different policies on when sonograms are performed — some only do an anatomy scan at 18 to 22 weeks, but others add in an early sonogram before 13 weeks to assess the health and/or age of the pregnancy. Also, some parents-to-be opt out of them completely by choice.
That being said, those early sonograms have the ability to identify a pregnancy that isn't where it needs to be: a significant advancement from pregnancy technology decades ago, when everything was one big surprise. An ectopic pregnancy, of course, is one of those unfortunate surprises, but if the sonogram is early enough, it can be discovered before the patient develops any symptoms.
"Prior to the common use of ultrasound technology, emergency rooms used to see ectopic pregnancies approximately two or three times a week when the patient presented with lower abdominal pain," says Dole. "Now, with the imaging technology, we often are able to identify the abnormal pregnancies before they become symptomatic."
If not diagnosed prior to developing symptoms, Ruiz says the pregnant person could experience abnormal uterine bleeding in the first trimester along with pelvic pain. This pelvic pain is often (but not always) felt on one side or the other, and if it is an ectopic pregnancy and it's not diagnosed and treated, it can rupture a fallopian tube and result in internal bleeding — and unfortunately, it can be fatal, he adds.
Treating an ectopic pregnancy
Once an ectopic pregnancy has been diagnosed, it needs to be removed, and the embryo will not survive.
"Most ectopic [pregnancies] can be treated medically with a medication called methotrexate if diagnosed early enough," says Ruiz. "Laparoscopic removal of the pregnancy from the tube or removal of the affected tube if the diagnosis is not made soon enough. The most serious cases may involve an open procedure — abdominal incision. A ruptured ectopic is a surgical emergency."
Ruiz adds that 25 years ago, ectopic pregnancy was one of the leading causes of maternal death in pregnancy.
Those who have experienced one ectopic pregnancy are 15 percent more likely to go through it again with a future pregnancy, and those who have experienced two are 50 percent more likely, Ruiz explains. However, keep in mind that if you've had an ectopic pregnancy, your doctor will likely follow you closely during a subsequent pregnancy, so a surprise repeat is unlikely.