Obstetrics Simplified - Diaa
It is the implantation of the fertilised ovum outside the normal uterine
- Common site (95%): the tubes.
- Rare sites (5%): The ovaries, a rudimentary horn of a bicornuate
uterus, broad ligaments, peritoneum and cervix.
Incidence: about 1:250.
The following risk factors have been implicated:
May prevent or retard the passage of the fertilised ovum into the uterine
cavity. These may result from:
- Previous inflammatory disease:
- It is the commonest risk factor. Ectopic pregnancy may occur
- Destruction of tubal ciliated epithelium resulting in reduction
or loss of the ciliary current.
- Intratubal adhesions resulting in partial tubal obstruction.
- Peritubal adhesions resulting in restricted tubal
- Previous pelvic surgery:
- Particularly reconstructive tubal surgery.
- Developmental abnormalities:
- as diverticulae, accessory ostia and tubal hypoplasia.
- Adjacent tumours:
- especially in the broad ligament resulting in distortion, stretching
or partial obstruction of the tube.
- Previous ectopic pregnancy:
- where conservative treatment was carried out.
- Intrauterine contraceptive device:
- due to its effect on tubal motility or increased incidence of
Premature implantation of the fertilised ovum in the tube may occur
- Premature shedding of the zona pellucida: from the fertilised ovum.
- Transperitoneal migration of the fertilised ovum to the contralateral
tube: this long journey leads to advanced development of the ovum that
it becomes ready for implantation when it reaches the tube. This was
proved by presence of the corpus luteum in the contralateral ovary in
50% of ectopic pregnancy.
- Presence of ectopic endometrium in the tube.
- The trophoblast develops in the fertilised ovum and invades deeply
into the tubal wall.
- Following implantation, the trophoblast produces hCG which maintains
the corpus luteum.
- The corpus luteum produces oestrogen and progesterone which change
the secretory endometrium into decidua. The uterus enlarges up to 8
weeks size and becomes soft.
- The tubal pregnancy does not usually proceed beyond 8-10 weeks
- lack of decidual reaction in the tube,
- the thin wall of the tube,
- the inadequacy of tubal lumen,
- bleeding in the site of implantation as trophoblast invades.
- Separation of the gestational sac from the tubal wall leads to its
degeneration, and fall of hCG level, regression of the corpus luteum
and subsequent drop in the oestrogen and progesterone level.
- This leads to separation of the uterine decidua with uterine bleeding.
Fate of tubal pregnancy
- Tubal mole:
- The gestational sac is surrounded by a blood clot and retained
in the tube.
- Tubal abortion:
- This occurs more if ovum had been implanted in the ampullary
portion of the tube.
- Separation of the gestational sac is followed by its expulsion
into the peritoneal cavity through the tubal ostium.
- Rarely, reimplantation of the conceptus occurs in another abdominal
structure leads to secondary abdominal pregnancy.
- If expulsion was complete the bleeding usually ceases but it
may continue due to incomplete separation or bleeding from the implantation
- Tubal rupture:
- More common if implantation occurs in the narrower portion of
the tube which is the isthmus.
- Rupture may occur in the anti-mesenteric border of the
tube. Usually profuse bleeding occurs → intraperitoneal haemorrhage.
- If rupture occurs in the mesenteric border of the tube
a broad ligament haematoma will occur.
- Short period of amenorrhoea:
- usually does not exceed 8-10 weeks. This may be lacking if the
ectopic pregnancy is disturbed before the next menstruation. This
may occur particularly with ectopic pregnancy in the interstitial
portion of the tube.
- is present in almost every case and precedes vaginal bleeding.
It may be:
- Aching due to tubal distension.
- Colicky in tubal abortion.
- Stabbing in tubal rupture.
- Shoulder pain if blood accumulates under the diaphragm.
- Bladder and rectal irritability in pelvic haematocele.
- Vaginal bleeding:
- Due to shedding of the decidua. It is usually slight and follows
- General examination:
- Breast signs of pregnancy.
- Abdominal examination:
- Lower abdominal tenderness and rigidity especially on one side
may be present.
- Vaginal examination:
- Bluish vagina and bluish soft cervix.
- Uterus is slightly enlarged and soft.
- Marked pain in one iliac fossa on moving the cervix from
side to side.
- Ill defined tender mass may be detected in one adnexa
in which arterial pulsation may be felt.
- The other manifestations depend upon the clinical variety of the
Undisturbed Tubal Pregnancy
It is the same general symptoms and signs mentioned before. The pain
is aching in nature and there is no vaginal bleeding.
The more common so it is called the classical picture of ectopic pregnancy.
- The general symptoms and signs are present.
- Fainting attacks due to pain and intraperitoneal haemorrhage.
- Nausea and vomiting due to peritoneal irritation.
- General examination:
- Anaemia of varying degree depending upon the blood loss.
- Pulse is usually rapid.
- Temperature slightly higher (up to 38oC ) due to absorption
of blood from the peritoneal cavity.
- Blood pressure: falls in proportion to the amount of internal
- Abdominal examination:
- Cullen’s sign: a periumbilical bluish discoloration may be present
due to absorption of the blood in the peritoneal cavity by lymphatics.
It is a late sign.
- Local examination:
- Boggy swelling in the cul-de-sac if pelvic haematocele is present.
The most dramatic although not the most common.
Short period of amenorrhoea (6-8 weeks) or even there is no missed period.
- Rapidly developed shock, with pallor, sweating, air hunger, rapid
thready pulse and hypotension.
- Shoulder tip pain and hiccoughs due to irritation of the phrenic
nerve of the diaphragm by accumulated blood when the patient lying down
- The abdomen is distended, rigid with generalised tenderness.
- Shifting dullness and periumbilical bluish discolouration
due to intraperitoneal haemorrhage.
The same as in general signs of ectopic, although it is undesirable as
it may induce more disruption and bleeding.
- Symptoms suggesting disturbed tubal pregnancy since a period of
- Pressure symptoms due to accumulation of blood in the Douglas pouch
as frequency of micturition, tenesmus and dyspareunia.
- A fixed tender swelling is felt in Douglas pouch.
- The uterus is slightly enlarged, soft and pushed forwards and the
external os is directed downwards.
- Aspiration of Douglas pouch (culdocentesis) may reveal blood which
does not clot on standing. If blood clots it means that needle has punctured
a blood vessel.
- Infection may be superadded and a pelvic abscess is formed.
Investigations of Ectopic Pregnancy
Urine pregnancy tests are positive in only 50-60% of ectopic. Detection
of β-hCG in the serum by ELISA or radioimmunoassay
are more sensitive and can detect very early pregnancy about 10 days after
fertilisation i.e. before the missed period.
- If the test is negative, normal and abnormal pregnancy including
ectopic are excluded.
- If the test is positive, ultrasonography is indicated.
- In normal pregnancy, the β-hCG level
is doubling every 48 hours during the first 42 days of gestation.
- Ectopic pregnancy usually shows less than 66% increase in b -hCG
level within 48 hours.
- Unfortunately, this is not specific to ectopic pregnancy. In 15%
of normal pregnancies as well as in abortions there is also slow doubling
N.B. Alpha-hCG subunit level is higher in ectopic pregnancy than normal
In general, a positive β-hCG test with empty
uterus by sonar indicates ectopic pregnancy. This is true if the ß-hCG is
at or above the threshold level in which an intrauterine gestational sac
can be detected. This is called discriminatory zone.
- Discriminatory hCG zones:
- Diagnosis of ectopic pregnancy is made if there is:
- An empty uterine cavity by abdominal sonography with b -hCG
value above 6000 mIU/ml.
- An empty uterine cavity by vaginal sonography with b -hCG
value above 2000 mIU/ml.
Serum progesterone level is lower in ectopic than normal pregnancy and
usually less than 15ng/ml.
If non-clotting blood is aspirated from the Douglas pouch through a wide
pored needle, intraperitoneal haemorrhage is diagnosed. But if not, ectopic
pregnancy cannot be excluded.
- If microscopic examination of the products of curettage reveals
decidua and chorionic villi, the condition is abortion of intrauterine
- If it reveals decidua only or Arias Stella reaction in the endometrium
as well (cellular atypism, mitotic activity and glandular proliferation),
ectopic pregnancy is diagnosed. The drawback is that in complete abortion
also decidua only is curetted.
A good diagnostic aid particularly in disturbed ectopic.
Complete blood picture
- Haemoglobin and haematocrit: to assess anaemia.
- Leucocytic count: exclude infections as appendicitis and salpingitis.
Uncommon Sites of Ectopic Pregnancy
Cornual angular pregnancy
- It is implantation in the interstitial portion of the tube.
- It is uncommon but dangerous because when rupture occurs bleeding
is severe and disruption is extensive that it needs hysterectomy.
- In some cases, the pregnancy is expelled into the uterus and
rupture does not occur.
Pregnancy in a rudimentary horn
- Pregnancy occurs in the blind rudimentary horn of a bicornuate uterus.
- As such a horn is capable of some hypertrophy and distension, rupture
usually does not occur before 16-20 weeks.
- Treatment: Excision of the horn. During operation, pregnancy in
a rudimentary horn can be differentiated from interstitial cornual tubal
pregnancy by finding the attachment of the round ligament lateral to
the first and medial to the later.
- Implantation in the substance of the cervix below the level of uterine
- May cause severe vaginal bleeding.
- Evacuation and cervical packing with haemostatic agent as fibrin
glue and gauze.
- If bleeding continues or extensive rupture occurs hysterectomy
- Pelvic adhesions.
- Favourable ovarian surface for implantation as in ovarian endometriosis.
- Fertilisation of the ovum inside the ovary or,
- implantation of the fertilised ovum in the ovary.
Spiegelberg criteria for diagnosis of ovarian pregnancy:
- The gestational sac is located in the region of the ovary,
- the ectopic pregnancy is attached to the uterus by the ovarian ligament,
- ovarian tissue in the wall of the gestational sac is proved histologically,
- the tube on the involved side is intact.
Laparotomy and inoculation of the ectopic pregnancy and reconstruction
of the ovary if possible. Otherwise, removal of the affected ovary is indicated.
Abdominal (peritoneal) pregnancy
- Primary: implantation occurs in the peritoneal cavity from the start.
- Secondary: usually after tubal rupture or abortion. Intraligamentous
pregnancy: is a type of abdominal but extraperitoneal pregnancy. It
develops between the anterior and posterior leaves of the broad ligament
after rupture of tubal pregnancy in the mesosalpingeal border or lateral
rupture of intramural (in the myometrium) pregnancy.
- of amenorrhoea followed by an attack of lower abdominal pain
and slight vaginal bleeding which subsided spontaneously.
- Abdominal examination:
- Unusual transverse or oblique lie.
- Foetal parts are felt very superficial with no uterine muscle
- Vaginal examination:
- The uterus is soft, about 8 weeks and separate from the foetus.
- No presenting part in the pelvis.
- Special investigations:
- Plain X-ray: shows abnormal lie. In lateral view, the foetus
overshadows the maternal spines .
- Ultrasound: shows no uterine wall around the foetus.
- Magnetic resonance imaging (MRI): has a particular importance
in preoperative detection of placental anatomic relationships.
Rupture of uterus.
The condition should be terminated surgically through laparotomy once
diagnosed as the foetus is malformed in the majority of cases. In addition,
there is risk of massive internal haemorrhage if separation of the placenta
At least 2000 ml of cross-matched blood should be on hand before proceeding
to laparatomy. The foetus is removed and if the placenta is attached to
an excisable structure as omentum, it is removed with it. If the placenta
is attached to an important structure leave it for autolysis which may extend
to few months or years. Any attempt to separate placenta will evoke uncontrollable
bleeding. In this case, methotrexate 12.5 mg IM daily for 5 days will destroy
trophoblastic tissue and accelerates the involution of the placenta.
In rare cases, the foetus may reach full term where spurious (false) labour
occurs and the foetus dies if not recognised.
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Edited by Aldo Campana,