Cervical Pregnancy (A 3D/4D Ultrasound Study)

Definition
Implantation of the fertilized ovum with subsequent development within
the cervical structure without involvement of the corpus uteri (below
the level of the internal os) results in cervical pregnancy.
This form of ectopic pregnancy has potentially life-threatening
consequences primarily due to hemorrhage (Baptisti, 1953; Pritchard and
MacDonald, 1980).


Incidence
Cervical pregnancy is an infrequent form of ectopic gestation.
The incidence is 1:16,000 gestations over a 15-year period (Sheldon et
al. 1963), 1:18,000 (Dees 1966), 1:2,400 pregnancies (Khosravi et al.,
1976);
The incidence is 1:7,040 pregnancies over an eight-year period
(Gitstein et al. 1979).
A remarkably high occurrence (1 in 1,000 pregnancies) was registered by
Shinagawa and Nagayama (1969) in Japan. This dramatic increase was
ascribed to the high number of artificial abortions performed in that
country.
Many early cervical pregnancies terminate in abortion due to the
unfavorable site of nidation and therefore elude detection or
misdiagnosed as early abortion or simply discarded because of lack of
sufficient proof (Resnick, 1962; Rothe and Birnbaum, 1973).


Etiology
The etiology of cervical pregnancy is consid¬ered unknown.
Several contributing factors include
· Previous sur¬gical trauma,
· Multiparity,
· High maternal age,
· Previous abortion,
· Uterine leiomyomas,
· Atro¬phy and malformation,
· Rapid tubal transport of the fertilized ovum,
· Abnormal timing of fertilization in relation to the menstrual
cycle,
· Previous cesarean section, and
· Recent use of oral contraceptives has been noted.

The definitive cause of implantation inside the cervical canal is not
known.
Four postulates had been provided to explain the ectopic nidation of
the ovum at this site.
1- Studdiford (1945) postulated rapid passage of the fertilized ovum
through the endometrial cavity as the cause of cervical implantation.
2- Schneider (1946) believed that the speed of travel of the ovum,
coupled with its rate of ripening, may determine the site of
implantation.
3- Ellingson (1950) proposed that an unfertilized ovum may reach the
cervical canal where implantation occurs.
4- Iffy (1962) suggested that delayed ovulation and fertilization in
relation to the menstrual cycle and displacement of the ovum by the
menstrual flow result in cervical implantation.


Classification According to the Site of Origin
David et al, (1980) have proposed a classification to simplify and
standardize the terminology.
1. Isthmico-cervical pregnancy: a very low lying placenta extending
from above, into the cervix.
2. Pure cervical pregnancy: very rarely reaches midpregnancy.
3. Cervico-isthmic pregnancy: transgres¬sion of a primary cervical
pregnancy upward into the isthmus.
4. Cervico-isthmic-corporal pregnancy: further involvement of the
corporate cavity.



Pathophysiology and Fate of Pregnancy
After implantation of the ovum in the cervix, the environment is not
capable of satisfying the needs of the growing ovum, since normal
placental attachment is hindered by the incomplete decidual reaction.
Direct invasion of trophoblastic tissue into the fibromuscular elements
of the cervix produces edema, necrosis, hemorrhage, and round cell
infiltration.
The pregnancy eventually terminates when invasion, erosion, or rupture
of a large vessel results in excessive bleeding.
Separation and expulsion of the products of conception may occur
through the external os, or the chorion may erode the cervical wall
with rupture into the vagina, parametrium, or the peritoneal cavity.
The insufficient decidual response in the cervix leads to abnormal
adherence of the placenta, accompanied by an incomplete separation and
profuse bleeding.
The evacuation of the products of conception usually results in
alarming bleeding since the cervix possesses little, if any,
contractile potential (Studdiford, 1945; Duckman and Amico, 1951). A
case of choriocarcinoma following a cervical pregnancy has been
reported by D'An¬tonio and Magumo (1969).


CLINICAL Presentations
Symptoms
1. Amenorrhea
Cervical pregnancy rarely progresses beyond the twentieth week of
gestation, however, exceptions do exist (Pisarski, 1960; Mi¬trani,
1973).
2. Pain
The majority of cases reveal no history of pain. The absence of pain in
the presence of vaginal bleeding has been considered characteristic of
this type of gestation. Primarily because the uterine body has no
involvement, contractions are not provoked, and painful cramps are not
felt (Resnick, 1962).
In advanced cases, cramping, lower abdominal pain and discomfort,
backache, and dysuria may be present (Mortimer and Aiken, 1968;
Gitstein et al., 1979).
3. Bleeding
Approximately half of the patients will experience spontaneous bloody
vaginal discharge or irregular vaginal bleeding with or without history
of amenorrhea. Severe bleeding may result from attempts to remove the
products of conception in patients with undiagnosed cervical
pregnancies who request termination of pregnancy.

Physical Findings:
On pelvic examination, the cervix appears distended and soft. The
products of conception may be felt within the cervical canal.
In early cervical pregnancy, the uterus is relatively firm and may be
mistaken for a myoma affixed to the pregnant uterus.
If the pregnancy continues, a mass resembling a pregnant uterus is felt
above the symphysis.
On top of this is found a smaller mass, the empty corpus uteri
(hourglass-shaped uterus).


DIAGNOSTIC CRITERIA
PATHOLOGIC CRITERIA:
The pathologic criteria for diagnosis of cervical pregnancy were set
forth by Rubin (1911).
1. Cervical glands must be opposite the placental attachment.
2. The attachment of the placenta to the cervix must be intimate.
3. The placenta must be situated, in whole or in part, either below the
entrance of the uterine vessels or below the peritoneal reflection on
the anterior and posterior surfaces of the uterus.
4. Fetal elements must not be present in the corpus uteri.

Rubin's criteria require pathologic examination of the excised uterus.
However, if the uterus is preserved, these criteria cannot be applied.
Therefore, Duckman (1951) suggested the following diagnostic criteria:
1. A dilated, thin-walled cervical canal containing histologic evidence
of ges¬tation.
2. A patulous external os, and
3. Small and firm corpus uteri with nor¬mal-size internal os resting
on top of the dilated cervix.


CLINIACAL CRITERIA:
Paalman and McElin (1959) offered several active clinical signs to
establish the diag¬nosis:
1. Amenorrhea followed by uterine bleeding without cramping pain.
2. A softened and disproportionately enlarged cervix equal to or larger
than, the corporal portion of the uterus (an hour¬glass-shaped
uterus).
3. Products of conception entirely confined within, and firmly attached
to, the endocervix.
4. A snug internal os.
5. Partially open external os.


SONOGRAPHIC CRITERIA:
Recently, ultrasonography has facilitated early diagnosis of cervical
pregnancy (Kobayashi et al, 1969; Raskin, 1978; Chow and Lindahl, 1979;
Gitstein et al, 1979).
The sonographic criteria for the diagnosis of cervical pregnancy are
the following:
1. Diffuse amorphous intrauterine echoes.
2. Empty uterus (absence of an intrauterine pregnancy where the double
ring gestational sac sign is not seen).
3. Uterine enlargement.
4. Characteristic enlargement of the cervix containing the products of
conception. Occasionally, a constricted isthmic portion (internal os)
is present.

The present author criteria are derived from a three dimensional study
in cases of suspected cervical ectopic pregnancy.
In the figures shown in the original document:
The four planner view of cervical ectopic pregnancy with surface
rendering and colour flow mapping demonstrates the following diagnostic
criteria:
1. Longitudinal plane of the uterus from the fundal line to the
external os. The uterus shows a decidual reaction with absence of the
double contoured gestational sac ring.
2. Transverse plane of the corporeal cervical zone,
3. Coronal plane of the uterus and cervix,
4. 3D view of the corporeal decidual cavity,
5. The junction area of the corpus and cervix at the point of entry of
the uterine vessels.
6. The cervical canal is expanded by gestational sac containing
embryonic complex and yolk sac with intimate penetration of the
chorionic shell into the cervical substance.
Both the internal and external os are closed. The uterine cavity is
empty.
7. The colour flow map of the area of interest shows the sparse
corporeal vascularisation in contradistinction with the very rich
cervical vascularisation which is remarkable below the point of entry
of the uterine vessels at the level of internal os. The vessels are
arranged in the form of ring-of-fire around the gestational sac.
The preoperative recognition of cervical, pregnancy will certainly be
enhanced by the increased use of ultrasonography in the evalu¬ation of
patients with vaginal bleeding during early pregnancy.
These ultrasonic features, coupled with painless first-trimester
bleeding, a distended cervix, and a slightly dilated external os should
suggest to the physician the possibility of cervical pregnancy.


DIFFERENTIAL DIAGNOSIS
Seldom is cervical pregnancy recognized clinically prior to surgery.
Nelson (1979) found that only 18 percent of patients were suspected of
having cervical pregnancy prior to operative intervention.
The most frequent preoperative diagnosis was imminent or incomplete
abortion.
The diagnosis is to be distinguished from the following complications
resembling cervical pregnancy:
1. The cervical phase of a uterine abortion, including septic abortion
(Gabbe et al, 1975).
2. Cervical abortion (spontaneous uterine abortion with retention of
the products of conception within the cervical canal due to a resisting
external cervical os, thereby ballooning out the cervical canal).

Duckman and Amico (1957) suggested the following criteria for
differentiation of cervical pregnancy from a cervical abortion:
1. The corpus above the distended cervix is usually larger in a
cervical abortion than in early cervical preg¬nancy.
2. In cervical abortion, both the internal and external os are dilated,
whereas in cervical pregnancy the internal os is virtually closed.
3. In cervical pregnancy, the external os is only partially dilated. In
a cervical abortion, the external os usually is closed until the
abortion is well advanced since this resistance to dilatation of the
external os is responsible for the entity.
4. In curettage of a cervical abortion, the placental tissue can be
palpated extending from the cervical canal though the internal os and
attached to the uterine wall.
5. Placenta previa.
6. Uterine or cervical neoplasia. The marked vascularity and friable
appearance of the gestational process can be confused with a neoplastic
condition. Profuse bleeding may occur if the products of conception and
cervix are mistaken for a tumor and biopsied.
7. Bleeding varicose veins of the portio.
8. Cervical myoma (Jeffcoate, 1975).


MANAGEMENT
SURGICAL MANAGEMENT
1. Abdominal Hysterectomy
The hemorrhage in cervical pregnancy can be massive and fatal. Nelson
(1979) found that approximately 90 percent required abdominal
hysterectomy to control the severe hemor¬rhage associated with this
condition. The average blood loss was 6.4 units.

2. Vaginal Cervicotomy (Matracaru operation)
Experience in Europe with conservative management of early cervical
pregnancy has been favorable (Dobrovici, 1968; Siliquini and DeSario,
1969; Parvulescu and Alexandrescu, 1969). A frequently used approach is
the so-called vaginal cervicotomy (Matracaru operation) or variations
of this technique (Matracaru et al., 1966; Matracaru, 1968).
The technique can be summarized as follows:
· Broad exposure of the pregnant cervix with the aid of adequate
vaginal re¬tractors.
· Fixing of the anterior lip of the cervix with two atraumatic
cervical clamps.
· Detachment of the urinary bladder.
· Ligature of the cervical branches of the uterine arteries.
· High cervicotomy on the anterior aspect of the cervix, broadly
exposing the endocervical cavity.
· Digital removal of the products of conception.
· Curettage of the endocervical cavity to remove adherent fragments.
· Clamping of bleeding sites and hemostasis with catgut sutures, if
required.
· Dilatation of the internal orifice with Hegar No. 5 to No. 8,
followed by curetting of the uterine cavity.
· Closure of the cervical edges in a single layer with thick catgut.
Cervical packing may be needed and removed after 24 hours.

3. Cervical Artery Ligation
Should packing fail to control the bleeding or if hemorrhage is profuse
during the curettage, the cervical branches of the uterine arteries can
be ligated.

4. Other Methods to control bleeding areas have been attempted,
including suturing the cervix, cervical cerclage, resection of the
bleeding placental area with reconstruction of the cervix, and cervical
amputation, all with some success in individual cases (Duckman, 195 1;
Dodek, 1965; Mortimer and Aiken, 1968; Rothe and Birnbaum, 1973; Barber
and Graber, 1974; Khosravi et al, 1976; Gitstein et al, 1979; Bernstein
et al., 1981).

5. Cervical Pregnancy Treated by Local Excision of the gestational sac
along with clamping and ligation of the cervix, followed by vaginal
packing has been reported (Whittle, 1976).

6. Successful management with cervical suture and intracervical
obturator was described recently. The cervix was compressed against a
stiff polyethylene Argyle sucker tube inserted in the cervical canal by
a 5-mm Mersilene Shirodkar-type suture. The obturator and the stitch
must remain undisturbed for several weeks (Woodforde and Diggory,
1978). 7. More recently, Nelson (1979) described successful
conservative management of cervical pregnancy utilizing bilateral
internal iliac artery ligation. Following ligation of the hypo¬gastric
arteries, the cervix was curetted and intracervical packing was
inserted.

Conservative Management
Conservative management involving curettage, cervical packing, ligation
of the cervical arteries, amputation, and suturing of the cervix was
rarely successful. The majority of the conservatively managed cervical
pregnancies were less than eight weeks. When the pregnancy progressed
beyond the eighth week, severe hemorrhage invariably occurred, and
hysterectomy was re¬quired.
Conservative management is desirable, if possible, to preserve the
childbearing function, especially in nulliparas. However, conservative
treatment should be attempted only in the most favorable cases by
experienced gynecologic surgeons. Very early pregnancies (six weeks or
less) may be terminated by careful curettage of the endocervix and
endometrium (Gitstein et al, 1979). Utmost care must be exercised to
avoid cervical rupture or uterine perforation while attempting to
remove the products of conception (Wiener, 1979).
Several techniques have been recommended with various results.
1. Packing:
To control bleeding, the endometrial cavity, dilated cervical canal,
and vagina have been packed with gauze or GEL ¬FOAM for counter
pressure. To create greater pressure, a tight packing of the cervical
canal and sewing of the external os together with interrupted sutures
over the packing have been attempted. Secondary hemorrhage may occur,
however, as much as four or five days later, and even up to six weeks
postoperatively after removal of the packing.
2. Methotrexate therapy.



Prognosis
The prognosis for future pregnancies following conservative management
is not well documented, although normal pregnancy followed by vaginal
delivery after a previous cervical pregnancy has been reported (Sheldon
et. al., 1963).
The risk of a subsequent cervical pregnancy is unknown.


REFERENCES
Baptisti, A., Jr.: Cervical pregnancy. Obstel. Gynecol.,1:353,1953.
Pritchard, J. A., and MacDonald, P. E.: Williams Obstetrics, 16th ed.
Appleton-Century-Crofts, New York, 1980.
Sheldon, R. S.; Aaro, L. A.: and Welch, J. S.: Conservative management
of cervical pregnancy. Am. J. Obstet. Gynecol., 87:504, 1963.
Dees, H. C.: Cervical pregnancy associated with uterine leiomyoma.
South. Med. J, 59:900,1966.
Khosravi, H.; Campbell, J. W.; and Giustini, F. G.: Cervical pregnancy:
Report of three cases and a review of the literature. Int. J. Gynecol.
obstet., 14:237, 1976.
Gitstein, S.; Ballas, S.; Schujman, E.; et al.: Early cervical
pregnancy: Ultrasonic diagnosis and conservative treat¬ment. Obstet.
Gynecol., 54:756,1979.
Shinagawa, S., and Nagayama, M.: Cervical pregnancyn a possible sequel
of induced abortion. Report of 19 cases. Am. J. Obstet. Gynecol.,
105:282, 1969.
Resnick, L.: Cervical pregnancy. S. Afr. Med. J, 36:73, 1962.
Studdiford, W. E.: Cervical pregnancy: A partial review of the
literature and a report of two probable cases. Am. J. Obstet. Gynecol.,
49:160, 1945.
David, M. P.; Bergman, A.; and Delighdish, L.: Cervic-isthmic pregnancy
carried to term. Obstet. Gynecol., 56:247, 1980.
D'Antonio, G., and Magurno, G.: Corionepitelioma da gravidanza
cervicale. Rass Int. Clin. Terr., 49-.1312,1969.
Pisarski, T. S.: Cervical pregnancy. Br. J. Obstet. Gynaecol., 67:759,
1960.
Mitrani, A.: Cervical pregnancy ending in a live birth. Br. J. Obstet.
Gynaecol., 80:761, 1973.
Mortimer, C. W., and Aiken, D. A.: Cervical pregnancy. Br. J. Obstet.
Gynaecol. 75:741, 1968.
Rubin, I. C.: Cervical pregnancy. Surg. Gynecol. Obstel.,13:625, 1911.
Paalman, R. J., and McElin, T. W.: Cervical pregnancy. Review of the
literature and presentation of cases. Am..J. Obstet. GynecoL, 77:1261,
1959.
Kobayashi, M.; Hillman, L. M. and Fillist, L. P.: Ultrasound, an aid in
the diagnosis of ectopic pregnancy. Am. J. Obstet. Gynecol., 103:1131,
1969.
Raskin, M. M.: Diagnosis of cervical pregnancy by ultrasound: A case
report. Am. J Obstel. GynecoL, 130:234, 1978.
Chow, T. T. S., and Lindahl, S.: Ectopic cervical pregnancv. J. Clin.
Ultrasound, 7:217, 1979.
Nelson, R. M.: Bilateral internal iliac artery ligation in cervical
pregnancy: Conservation of reproductive function. Am. J. Obstet.
Gvnecol, 134:145, 1979.
Gabbe, S. G.; Kitzmiller, J. L.; Kosasa, T. S.; et al: Cervical
pregnancy presenting as septic abortion. Am. J. Obstet. Gnecol.,
123:212,1975.
Jeffcoate, N.: Principles of Gynecology, 4th ed. Butterworths,
London,1975.
Wiener, W. B.: Cervical pregnancy: Report of a can. J.Miss. State Med.
Assoc., 20:1, 1979.
Rothe, D. J., and Birnbaum, S. J.: Cervical pregnancy: Diagnosis and
management. Obsiet. Gynecol., 42:675, 1973.
Barber, H. R. K.; and Graber, E. A. W. B.: Surgical Disease in
Pregnancy. Saunders, Philadelphia, 1974.
Bernstein, D.; HoIzinger, M.; Ovadia, J.; et al.: Conservative
treatment of cervical pregnancy. Obstet. Gynecol,58:741,1981.
Whittle, M. J.: Cervicalpregnancy managed by local excision. Br. Med.
J., 2:795, 1976.
Woodforde Scott, J., and Diggory, P. L. C.: Management of cervical
pregnancy with circumsuture and intracervical obturator. Br. Med. J,
1:825, 1978.
Dobrovici, V: A new surgical technique for the treatment of cervical
pregnancy in the course of the first ten weeks. Roumanian med. Rev.,
12:62,1968.
Siliquini, P. N., and DeSario, G. S.: Cervicografia e terapia
conservative nella gravidanza cervicale. Minerva Gine col., 21:460,
1969.
Parvulescu, I., and Alexandrescu, E.: Methode conservatoire dans la
grossesse cervicale. Bull. Soc. Roy. Belge. Gynecol. Obstet., 39:167,
1969.
Matracaru, G.: Eine neue handlung der zervikalen Schwangerschaft.
Zentralbl. Gynakol, 90:1264,1968.
Matracaru, G.; Constantinescu, P.; Iacob C.; et al.:
Cervicohysterosalpingography in cervical pregnancy. Am. J. obstet.
Gynecol., 94:929, 1966.
Dodek, S. M.: Cervical Pregnancy: Diagnosis and management. South. Med.
J.. 58:167, 1965.

Dr. Wael Tohamy
PanoramaScan.com Project Manager
email:
Url: http://www.panoramascan.com