Assisted reproduction techniques and ectopic pregnancy

An ectopic pregnancy or extrauterine pregnancy occurs when the embryo implants somewhere other than the uterine endometrium, usually in the fallopian tube. However, the uterus is the only organ capable of carrying a pregnancy, so the ectopic pregnancy must be terminated as soon as it is detected, to avoid possible complications for the mother.

There are predisposing factors that may increase a woman’s risk of having an ectopic pregnancy. Among them, assisted reproductive technologies (ART) are often included. However, there is some controversy about this, and the causes that may lead to this increased risk are not entirely clear.

The different sections of this article have been assembled into the following table of contents.

Risk factors for ectopic pregnancy

Ectopic or extrauterine pregnancy is the name given to a pregnancy complication that occurs when the embryo implants outside the uterine cavity. The most common location of an ectopic pregnancy is the fallopian tube (95%). However, ectopic pregnancy may also occur in other locations (such as the abdominal cavity, the cervix, or the ovary).

Among the risk factors described as possibly increasing the likelihood of an ectopic pregnancy are the following:

• Tubal factor: salpingitis, congenital malformations of the tubes...
• Pelvic or abdominal surgery.
• Pelvic inflammatory disease (PID).
• Endometriosis.
• Maternal age over 35 years.
• Smoking.
• Pregnancy with intrauterine device (IUD).
• Previous ectopic pregnancy.
• Assisted reproductive technologies (ART).

Factors that increase the risk of having an ectopic pregnancy

In this article, you can find more information about ectopic pregnancy and its risk factors: What is an ectopic pregnancy? – Types, symptoms, and diagnosis.

Ectopic pregnancy and assisted reproduction

Ectopic pregnancy can occur after natural conception (with an incidence of 1–2%) or following an assisted reproductive procedure (with an incidence described as up to four times higher).

As mentioned earlier, one of the main factors that may increase the risk of ectopic pregnancy is the tubal factor, when the fallopian tube is damaged due to pelvic inflammatory disease, prior surgery, etc.

However, tubal factor infertility is one of the common reasons why a couple may turn to assisted reproduction to achieve pregnancy. For this reason, it is expected that the incidence of ectopic pregnancy with assisted reproductive techniques, especially IVF, will be higher.

Relationship between ectopic pregnancy and assisted reproduction

Similarly, endometriosis has also been associated with an increased risk of ectopic pregnancy, due to the possible presence of endometrial tissue in the fallopian tubes.

On the other hand, maternal age over 35 years may also increase the likelihood of ectopic pregnancy. In this case, it is important to mention that the decrease in fertility with maternal age is one of the main reasons for resorting to assisted reproductive techniques.

For all these reasons, some experts believe that assisted reproductive techniques do not in themselves increase the risk of ectopic pregnancy, but that the risk appears higher compared to natural conception because of the underlying infertility that leads the couple to use these treatments.

Other possible risk factors related to IVF

Despite what was mentioned above, some factors have been proposed that could increase the risk of ectopic pregnancy in an in vitro fertilization cycle:

• Day-3 transfer. When an embryo is transferred on day 3, the time that elapses before potential implantation is longer than when a blastocyst is transferred, which increases the chance that the embryo could reach the fallopian tube.
• Transfer of more than one embryo. This may be related to day-3 transfers, as it used to be more common to transfer several embryos on day 3 of development. However, nowadays the tendency is to transfer a single embryo at the blastocyst stage.
• Fresh transfer. The explanation would be that the high hormone and estrogen levels during ovarian stimulation could create a tubal and uterine environment that favors ectopic pregnancy. Thus, vitrifying embryos and performing a deferred transfer would prevent this negative effect. The same would occur in egg donation treatments, since the patient does not undergo ovarian stimulation and therefore the potential risk of ectopic pregnancy would be lower.
• Thin endometrium. A thinner endometrium might be associated with a uterine lining less favorable for implantation, which could encourage the embryo to implant elsewhere. In contrast, an endometrium with adequate thickness could be a protective factor against ectopic pregnancy.

Ectopic pregnancy and IVF

Knowing all these possible factors may, to some extent, help reduce the incidence of ectopic pregnancy following assisted reproductive techniques.

FAQs from users

Can ectopic pregnancy be prevented after ART?

An ectopic pregnancy is a serious complication that can even put the woman's life at risk. Therefore, it deserves attention, even though the percentage of ectopic pregnancies is relatively low.

When resorting to assisted reproduction techniques, factors that may increase the risk of ectopic pregnancy should be taken into account and avoided (those that are avoidable), especially if there is a tubal factor. In this way, although the possibility of an ectopic pregnancy cannot be eliminated, the risk will be reduced.

In addition, knowing the risk factors and determining whether the risk of ectopic pregnancy is increased is the first step in being especially vigilant and detecting this complication early on. Early detection is essential to prevent the development of an ectopic pregnancy from leading to a ruptured fallopian tube, which would be a very serious complication.

On the other hand, increased monitoring and analytical and ultrasound control in a pregnancy achieved through assisted reproduction also favors early detection of a possible ectopic pregnancy.

Do assisted reproduction techniques increase the risk of ectopic pregnancy?

Ectopic pregnancy can occur after natural conception, with an incidence of about 1–2%, or after undergoing an assisted reproductive technique, with an incidence described as up to four times higher.

One of the main factors that may increase the risk of ectopic pregnancy is the tubal factor, when the fallopian tube is damaged due to pelvic inflammatory disease, previous surgery, and so on. However, tubal factor infertility is one of the common reasons why a couple may resort to assisted reproduction in order to achieve pregnancy. For this reason, it is expected that the incidence of ectopic pregnancy with assisted reproductive techniques, especially IVF, will be higher.
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Is there a higher probability of ectopic pregnancy after artificial insemination?

Yes. Compared to natural conception, the risk of ectopic pregnancy may be slightly higher with artificial insemination, although it would still be low. However, the specific cause of this increased risk is unknown.

Recommended readings

If you want to learn more about the risk factors for ectopic pregnancy, you can visit the following link: What are the causes and consequences of ectopic pregnancy?

On the other hand, if you want to know more about the treatment of ectopic pregnancy, we recommend reading this article: What is the treatment of ectopic pregnancy?

References