Abdominal pregnancy
Encyclopedia
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. While rare, abdominal pregnancies have a higher mortality rate than ectopic pregnancies in general but, on occasion, can lead to a delivery of a viable infant.
playing a major role. The maternal mortality rate is estimated to be about 5 per 1,000 cases, about seven times the rate for ectopics in general, and about 90 times the rate for a delivery (US data).
outside of the uterus, the rectouterine pouch (culdesac of Douglas), omentum
, bowel and its mesentery
, mesosalpinx
, and the peritoneum of the pelvic wall and the abdominal wall.. The growing placenta may be attached to several organs including tube and ovary. Rare other sites have been the liver
and spleen
. giving rise to a hepatic pregnancy or splenic pregnancy, respectively. Even an early diaphragmatic pregnancy has been described in a patient where an embryo began growing on the underside of the diaphragm
.
) between the uterus and the abdominal cavity, and the pregnancy is related solely to the peritoneal surface without signs that there was a tubal pregnancy first.
, vaginal bleeding
, and/or gastrointestinal symptoms. Frequently the diagnosis of an abdominal pregnancy is missed. However, it is a dangerous condition as it can bleed intraperitoneally resulting in a medical emergency
with hemorrhagic shock and can be fatal; other causes of maternal death in patients with an abdominal pregnancy include toxemia
, anemia
, pulmonary embolus, coagulopathy
, and infection.
Suspicion of an abdominal pregnancy is raised when the baby‘s parts can be easily felt, or the lie is abnormal. Sonography is extremely helpful in the diagnosis as it can demonstrate that the pregnancy is outside an empty uterus, there is no amniotic fluid
between the placenta and the fetus, no uterine wall surrounding the fetus, fetal parts are close to the abdominal wall, and the fetus is in abnormal lie. MRI has also been used with success to diagnose abdominal pregnancy. Elevated alpha-fetoprotein
levels are another clue of the presence of an abdominal pregnancy.
or laparotomy
, use of methotrexate
, embolization
, and combinations of these. The choice is largely dictated by the clinical situation. Generally, treatment is indicated when the diagnosis is made; however, the situation of the advanced abdominal pregnancy is more complicated.
. In those situations, live births have been reported, so in a report from Nigeria with four live births out of a series of 20 abdominal pregnancies. Often, however, with advancement of the pregnancy the support for the fetus becomes compromised and the fetus dies. A patient may carry a dead fetus but will not go into labor. Over time, the fetus calcifies and becomes a lithopedion
.
It is generally recommended to perform a laparotomy when the diagnosis of an abdominal pregnancy is made. However, if the pregnancy is past 24 weeks and the baby alive and medical support systems are in place, careful watching could be considered to bring the baby to viability (34–36 weeks). Women with an abdominal pregnancy will not go into labor. Delivery in a case of an advanced abdominal pregnancy will have to be via laparotomy
. The survival of the baby is reduced and high perinatal mortality
rates between 40-95% have been reported.
Babies of abdominal pregnancies often have birth defects due to compression in the absence of the amniotic fluid
buffer. The rate of malformations and deformations is estimated to be about 21%; typical deformations are facial and cranial asymmetries and joint abnormalities and the most common malformations are limb defects and central nervous malformations.
Once the baby has been delivered placenta
l management becomes an issue. In normal deliveries the contraction of uterus provides a powerful mechanism to control blood loss, however, in an abdominal pregnancy the placenta is located over tissue that cannot contract and attempts of its removal may lead to significant blood loss. Generally, unless the placenta can be easily tied off or removed, it may be preferable to leave it in place and allow for a natural regression. This process may take about four months and can be monitored by checking human chorionic gonadotropin
levels. Use of methotrexate
to accelerate placental regression is controversial as the large amount of necrotic tissue is a potential site for infection. Placental vessels have also been blocked by angiographic embolization
.
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...
where the pregnancy
Pregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
is implanted within the peritoneal cavity
Peritoneal cavity
The peritoneal cavity is a potential space between the parietal peritoneum and visceral peritoneum, that is, the two membranes that separate the organs in the abdominal cavity from the abdominal wall...
outside the fallopian tube or ovary and not located in the broad ligament. While rare, abdominal pregnancies have a higher mortality rate than ectopic pregnancies in general but, on occasion, can lead to a delivery of a viable infant.
Frequency
About 1% of ectopic pregnancies in the United States are abdominal, or about 10 out of every 100,000 pregnancies. A report from Nigeria places the frequency in that country at 34 per 100,000 deliveries. Risk factors are similar to tubal pregnancy with sexually transmitted diseaseSexually transmitted disease
Sexually transmitted disease , also known as a sexually transmitted infection or venereal disease , is an illness that has a significant probability of transmission between humans by means of human sexual behavior, including vaginal intercourse, oral sex, and anal sex...
playing a major role. The maternal mortality rate is estimated to be about 5 per 1,000 cases, about seven times the rate for ectopics in general, and about 90 times the rate for a delivery (US data).
Anatomy
Implantation sites includes the peritoneumPeritoneum
The peritoneum is the serous membrane that forms the lining of the abdominal cavity or the coelom — it covers most of the intra-abdominal organs — in amniotes and some invertebrates...
outside of the uterus, the rectouterine pouch (culdesac of Douglas), omentum
Omentum
Omentum may refer to:* greater omentum* lesser omentum...
, bowel and its mesentery
Mesentery
In anatomy, the mesentery is the double layer of peritoneum that suspends the jejunum and ileum from the posterior wall of the abdomen. Its meaning, however, is frequently extended to include double layers of peritoneum connecting various components of the abdominal cavity.-Mesentery :The...
, mesosalpinx
Mesosalpinx
The mesosalpinx is part of the lining of the abdominal cavity in higher vertebrates, specifically the portion of the broad ligament that stretches from the ovary to the level of the uterine tube....
, and the peritoneum of the pelvic wall and the abdominal wall.. The growing placenta may be attached to several organs including tube and ovary. Rare other sites have been the liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
and spleen
Spleen
The spleen is an organ found in virtually all vertebrate animals with important roles in regard to red blood cells and the immune system. In humans, it is located in the left upper quadrant of the abdomen. It removes old red blood cells and holds a reserve of blood in case of hemorrhagic shock...
. giving rise to a hepatic pregnancy or splenic pregnancy, respectively. Even an early diaphragmatic pregnancy has been described in a patient where an embryo began growing on the underside of the diaphragm
Thoracic diaphragm
In the anatomy of mammals, the thoracic diaphragm, or simply the diaphragm , is a sheet of internal skeletal muscle that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity from the abdominal cavity and performs an important function in respiration...
.
Primary versus secondary implantation
A primary abdominal pregnancy refers to a pregnancy that implanted directly in the abdominal cavity and its organs, save for the tubes and ovaries; such pregnancies are very rare, only 24 cases had been reported by 2007. Typically an abdominal pregnancy is a secondary implantation which means that it originated from a tubal (less common an ovarian) pregnancy and re-implanted. To diagnose the rare primary abdominal pregnancy, Studdiford's criteria need to be fulfilled: tubes and ovaries should be normal, there is no abnormal connection (fistulaFistula
In medicine, a fistula is an abnormal connection or passageway between two epithelium-lined organs or vessels that normally do not connect. It is generally a disease condition, but a fistula may be surgically created for therapeutic reasons.-Locations:Fistulas can develop in various parts of the...
) between the uterus and the abdominal cavity, and the pregnancy is related solely to the peritoneal surface without signs that there was a tubal pregnancy first.
Diagnosis
A patient with an abdominal pregnancy may just display the normal signs of pregnancy or have non-specific symptoms such as abdominal painAbdominal 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...
, 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...
, and/or gastrointestinal symptoms. Frequently the diagnosis of an abdominal pregnancy is missed. However, it is a dangerous condition as it can bleed intraperitoneally resulting in 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...
with hemorrhagic shock and can be fatal; other causes of maternal death in patients with an abdominal pregnancy include toxemia
Toxemia
Toxemia may refer to:* A generic term for the presence of toxins in the blood, see Bacteremia* An outdated medical term for Pre-eclampsia...
, anemia
Anemia
Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
, pulmonary embolus, coagulopathy
Coagulopathy
Coagulopathy is a condition in which the blood’s ability to clot is impaired. This condition can cause prolonged or excessive bleeding, which may occur spontaneously or following an injury or medical and dental procedures.The normal clotting process depends on the interplay of various proteins in...
, and infection.
Suspicion of an abdominal pregnancy is raised when the baby‘s parts can be easily felt, or the lie is abnormal. Sonography is extremely helpful in the diagnosis as it can demonstrate that the pregnancy is outside an empty uterus, there is no amniotic fluid
Amniotic fluid
Amniotic fluid or liquor amnii is the nourishing and protecting liquid contained by the amniotic sac of a pregnant woman.- Development of amniotic fluid :...
between the placenta and the fetus, no uterine wall surrounding the fetus, fetal parts are close to the abdominal wall, and the fetus is in abnormal lie. MRI has also been used with success to diagnose abdominal pregnancy. Elevated alpha-fetoprotein
Alpha-fetoprotein
Alpha-fetoprotein is a protein that in humans is encoded by the AFP gene....
levels are another clue of the presence of an abdominal pregnancy.
Treatment
Potential treatments consist of surgery with termination of the pregnancy (removal of the fetus) via laparoscopyLaparoscopy
Laparoscopy is an operation performed in the abdomen or pelvis through small incisions with the aid of a camera...
or 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 :...
, use of 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...
, embolization
Embolization
Embolization is a non-surgical, minimally-invasive procedure performed by an interventional radiologist and interventional neuroradiologists. It involves the selective occlusion of blood vessels by purposely introducing emboli.-Therapeutic applications:...
, and combinations of these. The choice is largely dictated by the clinical situation. Generally, treatment is indicated when the diagnosis is made; however, the situation of the advanced abdominal pregnancy is more complicated.
Advanced abdominal pregnancy
Advanced abdominal pregnancy refers to situations where the pregnancy continues past 20 weeks of gestationGestation
Gestation is the carrying of an embryo or fetus inside a female viviparous animal. Mammals during pregnancy can have one or more gestations at the same time ....
. In those situations, live births have been reported, so in a report from Nigeria with four live births out of a series of 20 abdominal pregnancies. Often, however, with advancement of the pregnancy the support for the fetus becomes compromised and the fetus dies. A patient may carry a dead fetus but will not go into labor. Over time, the fetus calcifies and becomes a lithopedion
Lithopedion
A lithopedion |stone]]; = child), or stone baby, is a rare phenomenon which occurs most commonly when a fetus dies during an abdominal pregnancy, is too large to be reabsorbed by the body, and calcifies on the outside, shielding the mother's body from the dead tissue of the baby and preventing...
.
It is generally recommended to perform a laparotomy when the diagnosis of an abdominal pregnancy is made. However, if the pregnancy is past 24 weeks and the baby alive and medical support systems are in place, careful watching could be considered to bring the baby to viability (34–36 weeks). Women with an abdominal pregnancy will not go into labor. Delivery in a case of an advanced abdominal pregnancy will have to be via 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 :...
. The survival of the baby is reduced and high perinatal mortality
Perinatal mortality
Perinatal mortality , also perinatal death, refers to the death of a fetus or neonate and is the basis to calculate the perinatal mortality rate. Variations in the precise definition of the perinatal mortality exist specifically concerning the issue of inclusion or exclusion of early fetal and...
rates between 40-95% have been reported.
Babies of abdominal pregnancies often have birth defects due to compression in the absence of the amniotic fluid
Amniotic fluid
Amniotic fluid or liquor amnii is the nourishing and protecting liquid contained by the amniotic sac of a pregnant woman.- Development of amniotic fluid :...
buffer. The rate of malformations and deformations is estimated to be about 21%; typical deformations are facial and cranial asymmetries and joint abnormalities and the most common malformations are limb defects and central nervous malformations.
Once the baby has been delivered placenta
Placenta
The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. "True" placentas are a defining characteristic of eutherian or "placental" mammals, but are also found in some snakes and...
l management becomes an issue. In normal deliveries the contraction of uterus provides a powerful mechanism to control blood loss, however, in an abdominal pregnancy the placenta is located over tissue that cannot contract and attempts of its removal may lead to significant blood loss. Generally, unless the placenta can be easily tied off or removed, it may be preferable to leave it in place and allow for a natural regression. This process may take about four months and can be monitored by checking human chorionic gonadotropin
Human chorionic gonadotropin
Human chorionic gonadotropin or human chorionic gonadotrophin is a glycoprotein hormone produced during pregnancy that is made by the developing embryo after conception and later by the syncytiotrophoblast .. Some tumors make this hormone; measured elevated levels when the patient is not...
levels. Use of 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...
to accelerate placental regression is controversial as the large amount of necrotic tissue is a potential site for infection. Placental vessels have also been blocked by angiographic embolization
Embolization
Embolization is a non-surgical, minimally-invasive procedure performed by an interventional radiologist and interventional neuroradiologists. It involves the selective occlusion of blood vessels by purposely introducing emboli.-Therapeutic applications:...
.