Heterotopic pregnancy means having two pregnancies at the same time with different implantations, one healthy intrauterine pregnancy (which occurs inside the uterus) and the other ectopic pregnancy (which occurs outside the uterus and usually in the fallopian tubes). Heterotopic pregnancies can be just as dangerous as ectopic pregnancies. What makes it difficult is that most parents hope to maintain a healthy pregnancy, but at the same time have to end an unhealthy pregnancy.
What is a Heterotopic Pregnancy?
A heterotopic pregnancy is a type of ectopic pregnancy. In a heterotopic pregnancy, beside an egg cell in the uterus, there is another egg cell in an ectopic area such as the fallopian tubes, abdominal cavity, cervix, where the fallopian tube connects to the uterus, on the ovary, which starts to grow at the same time.
The growth of the egg cell outside the uterus progresses to the point where it ruptures the fallopian tube. Heterotopic pregnancies are usually less likely to occur in normal pregnancies. According to studies, out of every 10,000 normal pregnancies, one may end up in a heterotopic pregnancy.
Heterotopic pregnancies are much more likely in pregnancies where the egg cell has been introduced into the uterus by assisted reproductive techniques (ART). Ectopic single pregnancy is much more likely than simultaneous intrauterine and extrauterine (heterotopic) pregnancies. When a person becomes pregnant using assisted reproductive techniques, it is much more likely that several egg cells will enter the uterus and the outside of the uterus at the same time.
Egg cell growth is dangerous anywhere except the uterus and causes many problems. Heterotopic pregnancy is a bit difficult to diagnose because in this type of pregnancies, the doctor pays more attention to the fetus inside the uterus, and this causes more than 60% of external cases of heterotopic pregnancy to be diagnosed when the fallopian tube ruptures.
How does a Heterotopic Pregnancy Occur?
Doctors believe that a decrease in HCG hormone and the occurrence of symptoms such as pain in the abdomen and pelvis are symptoms of ectopic pregnancy. The growth of another egg cell occurs a little later or occurs when the fallopian tube is torn and causes complications for the pregnant person. The radiologist should look more closely at pregnancy-related ultrasounds.
In pregnancies performed with assisted contraception, the radiologist should be aware of the type of pregnancy to be more careful when performing the ultrasound. Heterotopic pregnancies are more dangerous than ectopic pregnancies because they are a little more difficult to diagnose.
In heterotopic pregnancies, the egg grows outside the uterus until the growth site shrinks and ruptures the fallopian tubes or other complications. The patient is bleeding profusely, which can be life-threatening if she does not arrive at the hospital on time and the treatment process is not started as soon as possible.
Incidence and Risk Factors of Heterotopic Pregnancy
Heterotopic pregnancies have been rare in the past, estimated at 1 in 30,000 pregnancies. With the advent of ART, including superovulation, intrauterine insemination, and in vitro fertilization (IVF), the overall heterotopic pregnancy rate has increased to approximately 1 in 3900 pregnancies. An analysis of all registered ART pregnancies in the United States from 1999 to 2002 reported an incidence of 1.5 per 1,000 ART pregnancies.
The increase in the incidence of ART pregnancies may be due to the high proportion of patients with cervical disease, high levels of estradiol and progesterone, or the high number of transferred embryos or ovulated eggs in this population. Other factors such as the volume and viscosity of the transfer medium and the method of embryo transfer may also play a role.
All women of childbearing age with abdominal or pelvic pain, vaginal bleeding, or abnormal menstruation should be tested for pregnancy. The next step is to determine the location with an ultrasound examination, which can identify the intrauterine pregnancy sac at 4.5 to 5 weeks of pregnancy.
The vast majority of pregnancies are in the uterus and sometimes in the fallopian tubes. However, physicians should be vigilant and consider implantation in other locations, such as cesarean section (hysterotomy), abdomen, cervix, and ovary, as well as a combination of intrauterine and ectopic pregnancy (heterotopic pregnancy). Misdiagnosis of pregnancy implant site(s), and in turn improper management can lead to life-threatening rupture and bleeding.
Due to the rarity of some of these disorders, much of the information on clinical manifestations, diagnosis and treatment has been obtained from small series, case reports, and expert opinions. This makes it difficult to determine the optimal method for evaluating and managing them.
Symptoms of Heterotopic Pregnancy
A woman with a heterotopic pregnancy may or may not have symptoms. You should also keep in mind that half of these pregnancies are diagnosed with only a ruptured fallopian tube. Symptoms of this type of pregnancy include:
- Abnormal vaginal bleeding
- Mild to severe abdominal pain and cramping
- Flank pain
Seek emergency care if you have severe pain, heavy bleeding, weakness, and any other worrying symptoms, as a ruptured fallopian tube can be fatal if left untreated.
How Heterotopic Pregnancy is diagnosed?
It is difficult for doctors to diagnose heterotopic pregnancy in the early months of pregnancy. Women may experience vaginal bleeding or pain, but these symptoms also occur in normal pregnancies. Because the ultrasound examines only the uterus and fetus in the early months, it may not show up on the ultrasound.
If there is any doubt about the existence of this type of pregnancy, it is only from the fourth to the fifth week that the existence of this type of pregnancy is confirmed by ultrasound. In this case, the mother must have a blood test to fully confirm heterotopic pregnancy. Women who have used ART methods must also do all of these processes.
How is Heterotopic Pregnancy Treated?
An ectopic fetus cannot survive. If the surrounding tissue of the fetus ruptures spontaneously, there is severe bleeding and there is a risk of death for the mother. Therefore, these pregnancies should be terminated as soon as possible.
The good news is that there is no need to terminate a healthy intrauterine pregnancy. This stage requires surgery and may or may not require removal of the damaged fallopian tubes.
Can the Healthy Fetus Survive in a Heterotopic Pregnancy?
Although heterotopic pregnancies increase the risk of miscarriage (especially when tubal rupture occurs), about 67% of women can maintain an intrauterine pregnancy. Even though your other fetus is healthy, it is perfectly normal for you to grieve after losing a fetus in a heterotopic pregnancy. Allow this loss to be shared with people you trust and you will pass the trauma.
However heterotopic pregnancies are pretty rare, being aware of this type of pregnancy is a must for mothers-to-be and fathers-to-be. Early diagnosis is of utmost importance in this type of pregnancy and if the mother with heterotopic pregnancy is not treated timely, it can be fatal. Fortunately, there is a nearly 70% chance for the healthy birth of the intrauterine fetus in these cases.