Heterotopic pregnancy is a dangerous condition, and difficult to diagnose. It occurs when a woman gets pregnant normally, with a fertilized egg in her uterus, but there is also another fertilized egg outside her uterus. The location of the fertilized egg outside the uterus can vary, but it tends to end up in one of the fallopian tubes. This is called an ectopic pregnancy.
This type of pregnancy occurs very rarely in natural conception, and tends to happen more in assisted fertilization. Heterotopic pregnancy is also sometimes called multiple-sited pregnancy, combined ectopic pregnancy, or coincident pregnancy. In simpler terms, there are two embryos: one is an ectopic pregnancy and the other is a normal intrauterine pregnancy.
What Causes a Heterotopic Pregnancy?
Most heterotopic pregnancies occur as a result of assisted reproductive technology, or ART, which usually means IVF (in-vitro fertilization). Estimates are that from one out of 2,700 to one out of 900 artificially assisted pregnancies becomes heterotopic. With natural conception the odds drop to 1 in 30,000.
Although the cause of heterotopic pregnancy varies from one woman to the next, some of the more common causes are:
- History of pelvic inflammatory disease
- Surgical treatment for infertility
- Forces generated during embryo transfer, which is the surgical placement of an embryo in the uterus (part of the IVF procedure)
Heterotopic Pregnancy Symptoms
Determining the incidence of heterotopic pregnancy is difficult, but it is on the rise—possibly due to an increase in the rate of pelvic inflammatory disease, but mainly due to the growing use of ART. Only 10 percent of cases are detected before surgery becomes necessary, but there are symptoms to watch for:
- Pain, cramping, and spotting very early in pregnancy, in some cases before you are even aware you are pregnant (these are the same symptoms associated with ectopic pregnancy)
- Persistent rising pregnancy hormone levels (hCG levels) after an induced abortion or a miscarriage (this is something that your doctor can test you for)
- Frequent lower abdominal pain, especially one-sided
- Hyperemesis gravidarum (severe nausea and vomiting in early pregnancy) due to a high level of pregnancy hormones.
In most cases of heterotopic pregnancy, the ectopic embryo is in one of the fallopian tubes, but cases have been reported in which it was implanted in the cervix, ovaries, or other locations in the abdomen.
Diagnosing Heterotopic Pregnancies
Diagnosing a heterotopic pregnancy can be difficult because it is similar to an ectopic pregnancy—in fact, it is an ectopic pregnancy, one that occurs simultaneously with a normal pregnancy. Differential diagnosis is further complicated by the similarity of the symptoms of heterotopic pregnancy to a variety of other conditions, including appendicitis or ovarian cyst.
In most cases, your doctor will want to perform an ultrasound test. About 50 percent of the time, a heterotopic pregnancy will become evident only after a fallopian tube has ruptured, resulting in internal bleeding.
Heterotopic Pregnancy Treatment
Once you are diagnosed with a heterotopic pregnancy, there are two main treatment options, but this diagnosis will always require surgery. One option is a surgery called laparotomy, which is very similar to a C-section. This procedure involves making an incision in the abdominal area, either at your bikini line or vertically from your belly button down (a midline incision). The type of incision that will be used depends on your symptoms at the time the diagnosis is made, and how far along you are at the time, but midline incisions are almost never done for this type of surgery.
In most cases a laparoscopic approach is preferred. This is done by making a few small incisions in your abdomen, one in the belly button area and from 1–3 more tiny incisions lower down. The decision whether to do a full laparotomy or a minimally invasive laparoscopy is made on the basis of how stable you are at the time and the gestational age of the fetus at the time of the diagnosis. If the patient has lost a lot of blood internally and has low blood pressure or is in shock, the laparotomy approach is quicker.
The laparoscopic approach is less invasive than an open procedure. In this procedure the doctors fill the abdomen with a gas that causes the abdominal cavity to expand, which provides them with better visibility and more room to work. A long, thin tube is then inserted into one of the incisions; at the end of this tube is a video camera and a light. Other surgical instruments are inserted into the other incisions.
Laparoscopy is done more often than laparotomy because recovery time is quicker—in most cases the patient can go home the same day—and the risk of infection is less. Cosmetic considerations are another reason—there is considerably less scarring. The disadvantage to laparoscopy is that the surgeon has less room to work, cannot see as well, and has to manipulate tissue with remote tools rather than with his hands, which can make it more difficult to judge how much force he is applying.
Preservation of the intrauterine pregnancy is a top concern as well. This also factors into the decision whether to perform a laparotomy or take a laparoscopic approach. In many cases the fertilized egg inside the uterus can be saved; according to some sources, 65 percent of women who are treated for heterotopic pregnancies go on to deliver healthy, full-term babies.
Heterotopic Pregnancy Complications and Risks
Heterotopic pregnancy is a dangerous condition if it is not caught early on. Most patients do not see a doctor until the fallopian tube ruptures. This often results in excessive internal bleeding. The outcome of surgery tends to be the removal of the affected fallopian tube and ovary. This removal can reduce a woman’s chances of getting pregnant again, but it also saves the mother’s life.
Questions for Your Doctor
- Does this affect my chances of becoming pregnant again?
- Will I be able to save the pregnancy that is in the uterus?
- Will my entire Fallopian tube need to be removed, or just the affected area?