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ECTOPIC PREGNANCY - a patient's guide
Editorial Team
What is an ectopic pregnancy?
An ectopic pregnancy is one that occurs in an abnormal
place (outside the uterus). Ectopic pregnancies can occur
in many parts of the reproductive system, but more than
95% of all ectopic pregnancies occur in the fallopian tubes.
Other sites include the ovaries, the abdominal cavity, the
junction of the fallopian tube and uterus, and the cervix.
How and why does it happen?
Normally, once fertilised, the ovum (egg) moves down the
fallopian tube towards the uterus (womb), growing in size
and complexity to form the blastocyst (from which the embryo
and placenta will develop). Within days of conception, the
blastocyst attaches itself to the lining of the upper part
of the uterus (womb). However, if the passage of the fertilised
ovum along the fallopian tube is delayed, then the blastocyst
is 'ready' for attachment before it has reached the uterine
cavity; this will lead to a tubal pregnancy. Anything that
affects the passage of the blastocyst along the fallopian
tube may thus increase the likelihood of an ectopic pregnancy.
There are a number of risk factors for ectopic pregnancy,
most of which relate to damaged or altered fallopian tubes.
The following table categorises these factors according
to magnitude of risk, and for each category lists them in
decreasing order of risk. Note that for women who have had
a tubal ligation (sterilisation) or those who are using
an intrauterine contraceptive device (IUD), the chance of
any pregnancy is very slight; however, if they do become
pregnant, then there is a considerable likelihood that the
pregnancy will be ectopic.
Note also that the use of fertility treatments such as
IVF (in vitro fertilisation) is associated with an increased
risk of ectopic pregnancy; furthermore, if it does occur,
it is more likely to involve sites apart from the fallopian
tubes than an ectopic pregnancy that occurs after natural
conception.
Factors associated with ectopic pregnancy:
High
Risk
Moderate
Risk
Slight
Risk
Tubal surgery
Infertility
Previous abdominal/pelvic surgery
Tubal ligation (having been sterilised)
Previous genital infections
Cigarette smoking (now or in the past)
Previous ectopic pregnancy
Multiple sexual partners
Vaginal douching
Exposure of the mother to the hormone diethylstilboestrol
in utero (i.e. when
she was a foetus in her mother's womb)
First intercourse before age 18 years
Current use of an IUD
Known tubal damage or disease
How do I know if I have an ectopic pregnancy?
An ectopic pregnancy usually causes symptoms early in
the pregnancy, either because it begins to fail, or distends
the site of implantation. (Rarely, an ectopic pregnancy
may continue to develop like a normal one, e.g. within the
abdominal cavity, where the growing foetus can be accommodated.)
The symptoms are identical to those of a miscarriage occurring
in the first trimester (first 13 weeks of pregnancy), i.e.
vaginal bleeding and abdominal pain. The most common symptoms
are the combination of a missed period and abdominal pain.
The pain may vary from mild to severe, and the bleeding
may range from scanty to heavy, with clots and/or 'tissue'.
It is important to note that sometimes pain or bleeding
may not be present with ectopic pregnancy, thus the absence
of these symptoms does not altogether exclude it.
Other symptoms reported by women with ectopic pregnancy
include those related to pregnancy in general (e.g. breast
tenderness, nausea), dizziness or faintness, and shoulder
tip pain. The last two symptoms (dizziness/faintness and
shoulder tip pain) are particularly important as they suggest
significant internal bleeding.
If you are know you are pregnant, and experience abdominal
pain or vaginal bleeding, you should notify your doctor
immediately. Furthermore, any sexually active woman of childbearing
age who develops abdominal pain and/or vaginal bleeding
should be given a pregnancy test (even if she has had a
tubal ligation or is using an IUD) to rule out ectopic pregnancy
or miscarriage. (Pregnancy tests are so accurate nowadays
that a pregnant woman is extremely unlikely to have a negative
test result).
How is ectopic pregnancy confirmed?
As noted above, the symptoms of ectopic pregnancy are
identical to those of early miscarriage, and unfortunately,
the signs (i.e. the doctor's findings on examination) are
also usually non-specific. Nevertheless, a woman with suspected
ectopic pregnancy or miscarriage should have a careful examination
of her abdomen and pelvis (including an internal examination).
The doctor may note abdominal tenderness, cervical irritation
(pain when the doctor touches the cervix), fever, and rapid
heart rate and/or low blood pressure (indicating significant
blood loss). Occasionally the doctor feels a mass to one
side of the cervix during the internal examination; this
mass is the ectopic pregnancy itself. Unfortunately, this
'adnexal mass' is an unreliable sign: doctors may miss them
and sometimes feel them on the opposite side to the ectopic
pregnancy!
If there is evidence that an ectopic pregnancy has ruptured
(e.g. major internal bleeding), the woman is referred for
immediate surgery: either laparoscopy (a telescopic examination
of the abdomen and pelvic cavity) or laparotomy (surgery
to open the abdominal cavity). In most cases however, the
symptoms and signs of ectopic pregnancy do not confirm its
diagnosis, and further tests are required. In the USA various
diagnostic 'plans' have been proposed in order to identify
ectopic pregnancy as early as possible, but many of the
tests used are only available at the large academic hospitals
where the 'plans' were devised. At other sites, an ultrasound
of the abdomen and pelvis is usually performed first, using
an abdominal scanner or an intravaginal one. So-called 'transvaginal'
ultrasound is preferred in many centres, because it can
detect pregnancies earlier than a 'transabdominal' one.
The ultrasound may reveal a pregnancy developing normally
in the uterus or an obvious ectopic pregnancy. (Evidence
of a pregnancy includes a 'gestational sac' with an obvious
'foetal pole' or even a foetal heartbeat.) Unfortunately,
the ultrasound results are often unhelpful, with neither
a normal nor ectopic pregnancy being seen. Instead, the
uterus may appear normal (because the pregnancy is too early
to be seen) or show vague abnormalities. In such cases,
more tests are required. At this point, many women will
be referred for a laparoscopy, to both confirm the diagnosis
(and if ectopic pregnancy is found) to treat it.
In many hospitals in the USA, however, women with suspected
ectopic pregnancy who are not thought to be in imminent
danger instead have repeated blood tests (to measure levels
of the pregnancy hormone ?ь-hCG) and repeated ultrasound
examinations over the next few days. Some doctors diagnose
ectopic pregnancy on the basis of an ultrasound finding
of an 'empty uterus' when the ?ь-hCG level is above that
at which it is known that normal pregnancies are always
seen, but others rely on further tests in such cases, e.g.
a 'diagnostic curettage'. This is basically a 'D&C' followed
by examination of the 'curettings' to check if there is
any evidence of placental tissue. Presence of placental
tissue indicates that the pregnancy was a failing intrauterine
one (failing, because a normal pregnancy was not seen on
ultrasound); absence of placental tissue indicates that
the pregnancy must exist outside the uterus, and further
treatment is necessary.
How is ectopic pregnancy treated?
In the past, most women with an ectopic pregnancy died,
usually as a result of massive haemorrhage when it ruptured.
Fortunately this happens very rarely nowadays, as an ectopic
pregnancy is usually diagnosed and treated before rupture
occurs. Because of the risk of rupture, the condition is
usually treated by termination of the pregnancy, although
some stable patients in whom ?ь-hCG levels are declining
may merely be treated 'expectantly' - i.e. they are closely
observed.
There are two primary methods of ending an ectopic pregnancy:
either by surgery or the use of the drug methotrexate. Surgery
is most commonly performed by laparoscopy, and if possible,
involves removal of the ectopic pregnancy from its implantation
site, with preservation of the surrounding tissue. Thus,
for tubal pregnancies, a 'salpingostomy' is carried out,
whereby a slit is made in the fallopian tube over the bulging
ectopic pregnancy, and the pregnancy is removed. The tube
is then allowed to heal, and is thus preserved. However,
if the tube is sufficiently damaged (from rupture of the
ectopic pregnancy), then it is usually removed outright
(a 'salpingectomy').
In the 1990s, medical treatment with methotrexate has
been used increasingly to treat unruptured ectopic pregnancies
below a certain size, with the aim of preserving the fallopian
tube. Methotrexate targets rapidly dividing cells in the
body, and is usually used to treat certain forms of cancer
and conditions such as rheumatoid arthritis. It is used
in ectopic pregnancy, because the cells of the developing
foetus and placenta are rapidly dividing. Methotrexate is
usually given by an intramuscular injection, either as a
large single dose, or as smaller daily doses given over
a few days. The blood levels of ?ь-hCG must then be closely
followed, to check that they decline - a sign that the ectopic
pregnancy is terminating.
Methotrexate is associated with certain side-effects,
the most common of which are colicky abdominal pain, and
increased pelvic pain (which may be mistaken for rupture).
Other effects include nausea, diarrhoea, oral irritation,
hair loss, and liver upsets. However, these do not occur
as commonly as happens when the drug is used long-term (e.g.
for rheumatoid arthritis).
What are the risks of surgery and methotrexate?
The most important short-term risks of salpingostomy and
methotrexate are two-fold: that the ectopic pregnancy persists
and that it ruptures. Persistent ectopic pregnancy is indicated
by ?ь-hCG levels that do not decrease; it requires further
treatment (e.g. use of methotrexate after salpingostomy,
or a further dose of methotrexate if that was the primary
treatment). Ruptured ectopic pregnancy should be suspected
when there is increased abdominal pain or further bleeding,
and requires surgical intervention.
Will I still be able to get pregnant in future after
an ectopic pregnancy?
There have been many long-term studies that have looked
at the reproductive outcomes after the various forms of
treatment. After salpingectomy, 49% of those who wished
to become pregnant had a subsequent normal pregnancy; after
salpingostomy and methotrexate, the figure is closer to
60%.
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