Ovarian pregnancy
Encyclopedia
Ovarian pregnancy refers to an ectopic pregnancy
that is located in the ovary
. Typically the egg cell is not released or picked-up at ovulation
, but fertilized within the ovary
where the pregnancy implants. Such a pregnancy usually does not proceed past the first four weeks of pregnancy. An untreated ovarian pregnancy causes potentially fatal intraabdominal bleeding and thus may become a medical emergency
.
; only about 0.15-3% of ectopics occur in the ovary. The incidence has been reported to be about 1:3,000 to 1:7,000 deliveries
An ovarian pregnancy is usually understood to begin when a mature egg cell is not expelled or picked up from its follicle
and a sperm
enters the follicle and fertilizes the egg, giving rise to an intrafollicular pregnancy. It has also been debated that an egg cell fertilized outside of the ovary could implant on the ovarian surface, perhaps aided by a decidua
l reaction or endometriosis
. Ovarian pregnancies rarely go longer than 4 weeks; nevertheless, there is the possibility that the trophoblast
finds further support outside the ovary and thus may affect the tube and other organs. In very rare occasions the pregnancy may find a sufficient foothold outside the ovary to continue as an abdominal pregnancy
, and an occasional delivery has been reported.
. On pelvic examination a unilateral adnexal mass may be found. Typical symptoms are abdominal pain
and, to a lesser degree, vaginal bleeding
during pregnancy. Patients may present with hypovolemia or be in circulatory shock because of internal bleeding.
Ideally, ultrasound will show the location of the gestational sac
in the ovary, while the uterine cavity is "empty", and if there is internal bleeding, it can be identified. Because of the proximity of the tube, the sonographic distinction between a tubal and an ovarian pregnancy may be difficult. Serial hCG levels generally show not the normal progressive rise.
In a series of 12 patients the mean gestation age was 45 days.
Histologically, the diagnosis has been made by Spiegelberg criteria
on the surgical specimen of the removed ovary and tube. However, the tube and ovary are not usually removed as sonography allows for earlier diagnosis and surgeons strive to preserve the ovary. Prior to the introduction of Spiegelberg's criteria in 1878, the existence of ovarian pregnancy was in doubt; his criteria helped to identify the ovarian pregnancy from other ectopics:
An ovarian pregnancy can be mistaken for a tubal pregnancy or a hemorrhagic ovarian cyst or corpus luteum prior to surgery. Sometimes, only the presence of trophoblastic tissue during the histologic examination of material of a bleeding ovarian cyst shows that an ovarian pregnancy was the cause of the bleeding.
Traditionally, an explorative laparotomy
was performed, and once the ovarian pregnancy was identified, an oophorectomy
or salpingo-oophorectomy was performed, including the removal of the pregnancy. Today, the surgery can often be performed via laparoscopy
. The extent of surgery varies according to the amount of tissue destruction that has
occurred. Patients with an ovarian pregnancy have a good prognosis for future fertility and therefore conservative surgical management is advocated. Further, in attempts to preserve ovarian tissue, surgery may involve just the removal of the pregnancy with only a part of the ovary. This can be accomplished by an ovarian wedge resection
.
Ovarian pregnancies have been successfully treated with methotrexate
since it was introduced in the management of ectopic pregnancy in 1988.
An ovarian pregnancy can develop together with a normal intrauterine pregnancy; such a heterotopic pregnancy will call for expert management as not to endanger the intrauterine pregnancy.
Ectopic pregnancy
An ectopic pregnancy, or eccysis , is a complication of pregnancy in which the embryo implants outside the uterine cavity. With rare exceptions, ectopic pregnancies are not viable. Furthermore, they are dangerous for the parent, since internal haemorrhage is a life threatening complication...
that is located in the ovary
Ovary
The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...
. Typically the egg cell is not released or picked-up at ovulation
Ovulation
Ovulation is the process in a female's menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum . Ovulation also occurs in the estrous cycle of other female mammals, which differs in many fundamental ways from the menstrual cycle...
, but fertilized within the ovary
Ovary
The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...
where the pregnancy implants. Such a pregnancy usually does not proceed past the first four weeks of pregnancy. An untreated ovarian pregnancy causes potentially fatal intraabdominal bleeding and thus may become a medical emergency
Medical emergency
A medical emergency is an injury or illness that is acute and poses an immediate risk to a person's life or long term health. These emergencies may require assistance from another person, who should ideally be suitably qualified to do so, although some of these emergencies can be dealt with by the...
.
Incidence
Ovarian pregnancies are rare: the vast majority of ectopic pregnancies occur in the fallopian tubeFallopian tube
The Fallopian tubes, also known as oviducts, uterine tubes, and salpinges are two very fine tubes lined with ciliated epithelia, leading from the ovaries of female mammals into the uterus, via the utero-tubal junction...
; only about 0.15-3% of ectopics occur in the ovary. The incidence has been reported to be about 1:3,000 to 1:7,000 deliveries
Etiology and pathology
The etiology of ovarian pregnancy is unknown, specifically as the usual causative factors – pelvic inflammatory disease and pelvic surgery – implicated in tubal ectopic pregnancy seem to be uninvolved. There appears to be a link to the intrauterine device (IUD), however, it cannot be concluded that this is causative as it could be that IUDs prevent other but not ovarian pregnancies. Some have suggested that patients who undergo IVF therapy are at higher risk for ovarian pregnancy.An ovarian pregnancy is usually understood to begin when a mature egg cell is not expelled or picked up from its follicle
Ovarian follicle
Ovarian follicles are the basic units of female reproductive biology, each of which is composed of roughly spherical aggregations of cells found in the ovary. They contain a single oocyte . These structures are periodically initiated to grow and develop, culminating in ovulation of usually a single...
and a sperm
Sperm
The term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...
enters the follicle and fertilizes the egg, giving rise to an intrafollicular pregnancy. It has also been debated that an egg cell fertilized outside of the ovary could implant on the ovarian surface, perhaps aided by a decidua
Decidua
Decidua is the term for the uterine lining during a pregnancy, which forms the maternal part of the placenta. It is formed under the influence of progesterone and forms highly-characteristic cells.-Etymology:...
l reaction or endometriosis
Endometriosis
Endometriosis is a gynecological medical condition in which cells from the lining of the uterus appear and flourish outside the uterine cavity, most commonly on the ovaries. The uterine cavity is lined by endometrial cells, which are under the influence of female hormones...
. Ovarian pregnancies rarely go longer than 4 weeks; nevertheless, there is the possibility that the trophoblast
Trophoblast
Trophoblasts are cells forming the outer layer of a blastocyst, which provide nutrients to the embryo and develop into a large part of the placenta. They are formed during the first stage of pregnancy and are the first cells to differentiate from the fertilized egg...
finds further support outside the ovary and thus may affect the tube and other organs. In very rare occasions the pregnancy may find a sufficient foothold outside the ovary to continue as an abdominal pregnancy
Abdominal pregnancy
An abdominal pregnancy is a form of an ectopic pregnancy where the pregnancy is implanted within the peritoneal cavity outside the fallopian tube or ovary and not located in the broad ligament...
, and an occasional delivery has been reported.
Diagnosis
The diagnosis is made in asymptomatic pregnant women by obstetric ultrasonographyObstetric ultrasonography
Obstetric sonography is the application of medical ultrasonography to obstetrics, in which sonography is used to visualize the embryo or foetus in its mother's uterus...
. On pelvic examination a unilateral adnexal mass may be found. Typical symptoms are abdominal pain
Abdominal pain
Abdominal pain can be one of the symptoms associated with transient disorders or serious disease. Making a definitive diagnosis of the cause of abdominal pain can be difficult, because many diseases can result in this symptom. Abdominal pain is a common problem...
and, to a lesser degree, vaginal bleeding
Vaginal bleeding
Vaginal bleeding refers to bleeding in females that is either a physiologic response during the non-conceptional menstrual cycle or caused by hormonal or organic problems of the reproductive system. Vaginal bleeding may occur at any age, but always needs investigation when encountered in female...
during pregnancy. Patients may present with hypovolemia or be in circulatory shock because of internal bleeding.
Ideally, ultrasound will show the location of the gestational sac
Gestational sac
The gestational sac is the only available intrauterine structure that can be used to determine if an intrauterine pregnancy exists, until the embryo is identified....
in the ovary, while the uterine cavity is "empty", and if there is internal bleeding, it can be identified. Because of the proximity of the tube, the sonographic distinction between a tubal and an ovarian pregnancy may be difficult. Serial hCG levels generally show not the normal progressive rise.
In a series of 12 patients the mean gestation age was 45 days.
Histologically, the diagnosis has been made by Spiegelberg criteria
Spiegelberg criteria
The Spiegelberg criteria are four criteria used to identify ovarian ectopic pregnancies named after Otto Spiegelberg.- Description :Four criteria for differentiating ovarian from other ectopic pregnancies:...
on the surgical specimen of the removed ovary and tube. However, the tube and ovary are not usually removed as sonography allows for earlier diagnosis and surgeons strive to preserve the ovary. Prior to the introduction of Spiegelberg's criteria in 1878, the existence of ovarian pregnancy was in doubt; his criteria helped to identify the ovarian pregnancy from other ectopics:
- The gestational sacGestational sacThe gestational sac is the only available intrauterine structure that can be used to determine if an intrauterine pregnancy exists, until the embryo is identified....
is located in the region of the ovaryOvaryThe ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...
. - The gestational sac is attached to the uterusUterusThe uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
by the ovarian ligamentOvarian ligamentThe ovarian ligament is a fibrous ligament that connects the ovary to the lateral surface of the uterus....
. - Ovarian tissue is histologicallyHistologyHistology is the study of the microscopic anatomy of cells and tissues of plants and animals. It is performed by examining cells and tissues commonly by sectioning and staining; followed by examination under a light microscope or electron microscope...
proven in the wall of the gestational sac. - The oviductOviductIn non-mammalian vertebrates, the passageway from the ovaries to the outside of the body is known as the oviduct. The eggs travel along the oviduct. These eggs will either be fertilized by sperm to become a zygote, or will degenerate in the body...
on the affected side is intact (This criterion, however, holds not true for a longer ongoing ovarian pregnancy.).
An ovarian pregnancy can be mistaken for a tubal pregnancy or a hemorrhagic ovarian cyst or corpus luteum prior to surgery. Sometimes, only the presence of trophoblastic tissue during the histologic examination of material of a bleeding ovarian cyst shows that an ovarian pregnancy was the cause of the bleeding.
Management
Ovarian pregnancies are dangerous and prone to internal bleeding. Thus, when suspected, intervention is called for.Traditionally, an explorative laparotomy
Laparotomy
A laparotomy is a surgical procedure involving a large incision through the abdominal wall to gain access into the abdominal cavity. It is also known as coeliotomy.- Terminology :...
was performed, and once the ovarian pregnancy was identified, an oophorectomy
Oophorectomy
Oophorectomy is the surgical removal of an ovary or ovaries. The surgery is also called ovariectomy, but this term has been traditionally used in basic science research describing the surgical removal of ovaries in laboratory animals...
or salpingo-oophorectomy was performed, including the removal of the pregnancy. Today, the surgery can often be performed via laparoscopy
Laparoscopy
Laparoscopy is an operation performed in the abdomen or pelvis through small incisions with the aid of a camera...
. The extent of surgery varies according to the amount of tissue destruction that has
occurred. Patients with an ovarian pregnancy have a good prognosis for future fertility and therefore conservative surgical management is advocated. Further, in attempts to preserve ovarian tissue, surgery may involve just the removal of the pregnancy with only a part of the ovary. This can be accomplished by an ovarian wedge resection
Wedge resection
Wedge resection is a surgical procedure to remove a triangle-shaped slice of tissue. It may be used to remove a tumor or some other type of tissue that requires removal and typically includes a small amount of normal tissue around it....
.
Ovarian pregnancies have been successfully treated with methotrexate
Methotrexate
Methotrexate , abbreviated MTX and formerly known as amethopterin, is an antimetabolite and antifolate drug. It is used in treatment of cancer, autoimmune diseases, ectopic pregnancy, and for the induction of medical abortions. It acts by inhibiting the metabolism of folic acid. Methotrexate...
since it was introduced in the management of ectopic pregnancy in 1988.
An ovarian pregnancy can develop together with a normal intrauterine pregnancy; such a heterotopic pregnancy will call for expert management as not to endanger the intrauterine pregnancy.