Ectopic pregnancy
Ectopic pregnancy is a complication of pregnancy in which the embryo attaches outside the uterus. This complication has also been referred to as an extrauterine pregnancy. Signs and symptoms classically include abdominal pain and vaginal bleeding, but fewer than 50 percent of affected women have both of these symptoms. The pain may be described as sharp, dull, or crampy. Pain may also spread to the shoulder if bleeding into the abdomen has occurred. Severe bleeding may result in a fast heart rate, fainting, or shock. With very rare exceptions, the fetus is unable to survive.
Overall, ectopic pregnancies annually affect less than 2% of pregnancies worldwide. Risk factors for ectopic pregnancy include pelvic inflammatory disease, often due to chlamydia infection; tobacco smoking; endometriosis; prior tubal surgery; a history of infertility; and the use of assisted reproductive technology. Those who have previously had an ectopic pregnancy are at much higher risk of having another one. Most ectopic pregnancies occur in the fallopian tube, which are known as tubal pregnancies, but implantation can also occur on the cervix, ovaries, caesarean scar, or within the abdomen. Detection of ectopic pregnancy is typically by blood tests for human chorionic gonadotropin and ultrasound. This may require testing on more than one occasion. Other causes of similar symptoms include: miscarriage, ovarian torsion, and acute appendicitis.
Prevention is by decreasing risk factors, such as chlamydia infections, through screening and treatment. While some ectopic pregnancies will miscarry without treatment, the standard treatment for ectopic pregnancy is a procedure to either remove the embryo from the fallopian tube or to remove the fallopian tube altogether. The use of the medication methotrexate works as well as surgery in some cases. Specifically, it works well when the beta-HCG is low and the size of the ectopic is small. Surgery such as a salpingectomy is still typically recommended if the tube has ruptured, there is a fetal heartbeat, or the woman's vital signs are unstable. The surgery may be laparoscopic or through a larger incision, known as a laparotomy. Maternal morbidity and mortality are reduced with treatment.
The rate of ectopic pregnancy is about 11 to 20 per 1,000 live births in developed countries, though it may be as high as 4% among those using assisted reproductive technology. It is the most common cause of death among women during the first trimester at approximately 6-13% of the total. In the developed world outcomes have improved while in the developing world they often remain poor. The risk of death among those in the developed world is between 0.1 and 0.3 percent while in the developing world it is between one and three percent. The first known description of an ectopic pregnancy is by Al-Zahrawi in the 11th century. The word ectopic means 'out of place'.
Signs and symptoms
Up to 10% of those with ectopic pregnancy have no symptoms, and one-third have no medical signs. In many cases the symptoms have low specificity, and can be similar to those of other genitourinary and gastrointestinal disorders, such as appendicitis, salpingitis, rupture of a corpus luteum cyst, miscarriage, ovarian torsion or urinary tract infection. Clinical presentation of ectopic pregnancy occurs at a mean of 7.2 weeks after the last normal menstrual period, with a range of four to eight weeks. Later presentations are more common in communities deprived of modern diagnostic abilities.Signs and symptoms of ectopic pregnancy include increased hCG, vaginal bleeding, sudden lower abdominal pain, pelvic pain, a tender cervix, an adnexal mass, or adnexal tenderness. In the absence of ultrasound or hCG assessment, heavy vaginal bleeding may lead to a misdiagnosis of miscarriage. Nausea, vomiting and diarrhea are more rare symptoms of ectopic pregnancy.
Rupture of an ectopic pregnancy can lead to symptoms such as abdominal distension, tenderness, peritonism and hypovolemic shock. Someone with a ruptured ectopic pregnancy may experience pain when lying flat and may prefer to maintain an upright posture, as intrapelvic blood flow can lead to swelling of the abdominal cavity and cause additional pain.
Complications
The most common complication is rupture with internal bleeding, which may lead to hypovolemic shock. Damage to the fallopian tubes can lead to difficulty becoming pregnant in the future. The woman's other fallopian tube may function sufficiently for pregnancy. After the removal of one damaged fallopian tube, pregnancy remains possible in the future. If both are removed, in-vitro fertilization remains an option for women hoping to become pregnant.Causes
There are several risk factors for ectopic pregnancies. However, in as many as one-third to one-half no risk factors can be identified. Risk factors include: pelvic inflammatory disease, infertility, use of an intrauterine device, previous exposure to diethylstilbestrol, tubal surgery, intrauterine surgery, smoking, previous ectopic pregnancy, endometriosis, and tubal ligation. A previous induced abortion does not appear to increase the risk. The IUD does not increase the risk of ectopic pregnancy, but with an IUD if pregnancy occurs it is more likely to be ectopic than intrauterine. The risk of ectopic pregnancy after chlamydia infection is low. The exact mechanism through which chlamydia increases the risk of ectopic pregnancy is uncertain, though some research suggests that the infection can affect the structure of fallopian tubes.Tube damage
Tubal pregnancy is when the egg is implanted in the fallopian tubes. Hair-like cilia located on the internal surface of the fallopian tubes carry the fertilized egg to the uterus. Fallopian cilia are sometimes seen in reduced numbers after an ectopic pregnancy, leading to a hypothesis that cilia damage in the fallopian tubes is likely to lead to an ectopic pregnancy. Women who smoke have a higher chance of an ectopic pregnancy in the fallopian tubes. Smoking leads to risk factors of damaging and destroying cilia. As cilia degenerate, the amount of time it takes for the fertilized egg to reach the uterus will increase. The fertilized egg, if it does not reach the uterus in time, will hatch from the non-adhesive zona pellucida and implant itself inside the fallopian tube, thus causing ectopic pregnancy.Women with pelvic inflammatory disease have a high occurrence of ectopic pregnancy. This results from the build-up of scar tissue in the fallopian tubes, causing damage to the cilia. However, if both tubes were completely blocked, so that sperm and egg were physically unable to meet, then fertilization of the egg would naturally be impossible, and neither normal pregnancy nor ectopic pregnancy could occur. Intrauterine adhesions present in Asherman's syndrome can cause ectopic cervical pregnancy or, if adhesions partially block access to the tubes via the ostia, ectopic tubal pregnancy. Asherman's syndrome usually occurs from intrauterine surgery, most commonly after D&C. Endometrial/pelvic/genital tuberculosis, another cause of Asherman's syndrome, can also lead to ectopic pregnancy as infection may lead to tubal adhesions in addition to intrauterine adhesions.
Tubal ligation can predispose to ectopic pregnancy. Reversal of tubal sterilization carries a risk for ectopic pregnancy. This is higher if more destructive methods of tubal ligation have been used than less destructive methods. A history of a tubal pregnancy increases the risk of future occurrences to about 10%. This risk is not reduced by removing the affected tube, even if the other tube appears normal. The best method for diagnosing this is to perform an early ultrasound.
Endometriosis
Endometriosis is a disease in which cells similar to those of the endometrium, the tissue covering the inside of the uterus, grow outside the uterus. An embryo attaching to such lesions leads to an ectopic pregnancy. The results of a 30-year study of reproductive and pregnancy outcomes, involving 14,000+ women of childbearing age, were presented at the 2015 European Society of Human Reproduction and Embryology annual congress. 39% of the study group had surgically confirmed endometriosis. Compared to their peers, the endometriosis subgroup had a 76% higher risk for miscarriage and a 270% higher risk for ectopic pregnancy. The higher risk of endometriosis was attributed to increased pelvic inflammation and structural and functional changes in the uterine lining.Other
Although some investigations have shown that patients may be at higher risk for ectopic pregnancy with advancing age, it is believed that age is a variable that could act as a surrogate for other risk factors. Vaginal douching is thought by some to increase ectopic pregnancies. Women exposed to DES in utero also have an elevated risk of ectopic pregnancy. However, DES has not been used since 1971 in the United States. It has also been suggested that pathologic generation of nitric oxide through increased iNOS production may decrease tubal ciliary beats and smooth muscle contractions and thus affect embryo transport, which may consequently result in ectopic pregnancy. Low socioeconomic status may also be a risk factor for ectopic pregnancy.Diagnosis
An ectopic pregnancy should be considered as the cause of abdominal pain or vaginal bleeding in everyone who has a positive pregnancy test. The primary goal of diagnostic procedures in possible ectopic pregnancy is to triage according to risk rather than establishing pregnancy location.Transvaginal ultrasonography
An ultrasound showing a gestational sac with the fetal heart in the fallopian tube has a very high specificity for ectopic pregnancy. It involves a long, thin transducer, covered with the conducting gel and a plastic/latex sheath and inserted into the vagina. Transvaginal ultrasonography has a sensitivity of at least 90% for ectopic pregnancy. The diagnostic ultrasonographic finding in ectopic pregnancy is an adnexal mass that moves separately from the ovary. In around 60% of cases, it is an inhomogeneous or a noncystic adnexal mass, sometimes known as the "blob sign". It is generally spherical, but a more tubular appearance may be seen in the case of hematosalpinx. This sign has been estimated to have a sensitivity of 84% and a specificity of 99% in diagnosing ectopic pregnancy. In the study estimating these values, the blob sign had a positive predictive value of 96% and a negative predictive value of 95%. The visualization of an empty extrauterine gestational sac is sometimes known as the "bagel sign", and is present in around 20% of cases. In another 20% of cases, there is visualization of a gestational sac containing a yolk sac or an embryo. Ectopic pregnancies where there is visualization of cardiac activity are sometimes termed "viable ectopic".The combination of a positive pregnancy test and the presence of what appears to be a normal intrauterine pregnancy does not exclude ectopic pregnancy, since there may be either a heterotopic pregnancy or a "", which is a collection of within the endometrial cavity that may be seen in up to 20% of women.
A small amount of anechogenic-free fluid in the recto-uterine pouch is commonly found in both intrauterine and ectopic pregnancies. The presence of echogenic fluid is estimated at between 28 and 56% of women with an ectopic pregnancy, and strongly indicates the presence of hemoperitoneum. However, it does not necessarily result from tubal rupture but is commonly a result from leakage from the distal tubal opening. As a rule of thumb, the finding of free fluid is significant if it reaches the fundus or is present in the vesico-uterine pouch. A further marker of serious intra-abdominal bleeding is the presence of fluid in the hepatorenal recess of the subhepatic space.
, Doppler ultrasonography is not considered to significantly contribute to the diagnosis of ectopic pregnancy.
A common misdiagnosis is of a normal intrauterine pregnancy is where the pregnancy is implanted laterally in an arcuate uterus, potentially being misdiagnosed as an interstitial pregnancy.