In this lecture, I’ll be reviewing ectopic pregnancy. This is important for you to listen to
as you can see questions on your USLME. In addition, you can save a life by understanding
the pathophysiology of an ectopic pregnancy. An ectopic pregnancy essentially is a pregnancy
that is developing outside of the uterus. This can happen in several locations.
Let’s review some of those locations now. An ectopic pregnancy is more likely to occur in the ampulla.
Over 70% of ectopic pregnancies occur here. Do you know why? I’ll wait for you to answer that.
If you guessed because fertilization occurs here then you are correct. There are other regions
that an ectopic pregnancy can implant including the isthmus and the fimbria.
3% of all ectopics occur on the ovary. Sometimes you can have an ectopic in the interstitium.
This is the junction between the tube and the uterus. 1% of all ectopics are abdominal.
This is extremely rare. However, we are seeing a surge in cervical ectopics.
These ectopics can be life-threatening as sometimes they look like a miscarriage.
If you try to extract them, the patient can lose her blood supply very quickly. This is very life threatening.
An ectopic pregnancy looks like this upon laparoscopy. They account for 1% to 2% of all pregnancies.
They account for 5% of all assisted reproductive technology pregnancies. For more information about ART,
please refer to that lecture slide. There are some definitive risk factors for an ectopic pregnancy
such as previous surgery on the tube. Any surgery but especially tubal ligation
can cause ectopics to occur. Tubal pathology from pelvic infection such as PID can also lead to ectopic.
DES exposure increases the risk five-fold. However, less patients exposed to DES
are now in their perimenopause and menopausal stages. So, you're unlikely to see this
but you may be tested on your exam. Also, patients who have infertility who have any type
of ART are two-fold increased risks. They are more likely to have a heterotopic.
That means one ectopic and one normal intrauterine pregnancy or IUP. Patients who smoke
are more likely to have an ectopic. There’s a two-fold increased risk. So, you should encourage
all of your patients to stop smoking for their own health benefit but of course, for the benefit
of any pregnancy that may occur. Contraception, we think that taking contraception
decreases the incidence or absolute risk of ectopic. However, there are some times
when the contraceptive method may fail and there's an increased risk of ectopic
if you conceived with an IUD in place. Again, if you’ve had permanent sterilization,
these patients are more likely to have ectopic if they become pregnant after the sterilization.
One third of pregnancies from sterilization are an ectopic. The diagnosis is easy.
A beta positive hCG usually occurs eight to ten days after ovulation. There is some time that is required
to determine what the character of the beta-hCG will be. Will it double normally every two to three days
or will it plateau? Serial beta-hCG determinations are more difficult to interpret in the setting of ART
possibly because there may be more than one gestation and therefore, the beta-hCG is elevated.
Let’s now look at what a normal pregnancy looks like. With an IUP, you have a gestational sac
usually at 38 days after the onset of menses. Then, you should see a fetal pole and a yolk sac.
Perhaps, you'll see the yolk sac such as the one pictured here, which is an indication
that there is an intrauterine pregnancy. However, you can't see a yolk sac in the adnexa.
So, it’s important to look at the ultrasound pictures to determine where the yolk sac
and therefore the IUP should be. An abnormal pregnancy would actually look like this.
This is an observation of a gestational sac with a yolk sac, an embryo, and fetal cardiac activity
outside of the uterus. This establishes the diagnosis of an ectopic. Typically, we don’t always see
very well like the last image. So, sometimes if we suspect an abnormal pregnancy
which could be an abnormal IUP, intrauterine pregnancy or an ectopic, we recommend doing
some type of uterine curettage. This can be done with manual vacuum aspiration
or a dilation and curettage. We typically do this when the beta-hCG is above the discriminatory zone
but there is no IUP seen on ultrasound. Typically, if you recover villi, this will exclude ectopic
and will tell you it was an abnormal IUP. However, it does not rule out the chance of a heterotopic.
Let’s talk about the medical management of ectopic pregnancy. Methotrexate is an effective
first-line medical therapy. It works by inactivating dihydrofolate reductase
and inhibiting DNA and RNA synthesis. It is the preferred alternative to surgical treatment.
However, the patient needs to meet some criteria. She needs to be hemodynamically stable.
She must not have any evidence of acute or intra-abdominal bleeding. She must be compliant
with the medication and is scheduled to come back to check her titers of beta-hCG.
Methotrexate does have some contraindications. If the woman is currently breastfeeding,
she cannot take Methotrexate. If she’s immunodeficient such as HIV positive or has AIDS,
she is not a candidate for Methotrexate. If the patient has cirrhosis or hepatitis,
she is not a candidate for Methotrexate. If she has renal failure, she should not receive Methotrexate.
Any bleeding dyscrasias or blood dyscrasias are also a contraindication. Sometimes patients report
a history of sensitivity to Methotrexate. They should also not receive Methotrexate.
Any active pulmonary disease such as an ongoing asthma exacerbation should not permit
the use of Methotrexate in these patients. Also, if a patient has active peptic ulcer disease,
she should not receive Methotrexate to treat her ectopic. I’d now like to review the surgical treatment
for ectopic pregnancy. We traditionally do this via laparoscopy and not laparotomy.
I can either perform a salpingostomy or a salpingectomy. A salpingostomy allows me to make
a linear antimesenteric incision on the fallopian tube. Then I remove the ectopic pregnancy
through the incision sometimes with hydrodissection. The incision is then allowed to close
by secondary intention. For a salpingectomy, the entire tube is removed. With salpingectomy,
we try to avoid this so the patient can have access to both her tubes even after having an ectopic.
About 65% of patients who’ve had an ectopic in a tube will go on to have an IUP or an intrauterine pregnancy.
Thank you for listening and good luck on your exam.