Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital at ChiaYi
Ectopic and Molar Pregnancy
By Dr. CJ Tsengg
While most pregnancies result in the birth of a healthy baby, occasionally a pregnancy goes wrong right from the start. Ectopic and molar pregnancies are examples of this. Sadly, neither ectopic nor molar pregnancies can result in the birth of a baby. And without prompt treatment, both can endanger the life of the pregnant woman.
What is an ectopic pregnancy?
Up to one pregnancy in 50 is ectopic, which means "out of place." In an ectopic pregnancy, the fertilized egg implants outside of the uterus, usually in the fallopian tube, and begins to grow. Rarely, an ectopic pregnancy can implant within the woman abdomen, on the outside of the uterus, on an ovary or in the cervix.
What are the symptoms of an ectopic pregnancy?
Some women with an ectopic pregnancy start out with typical early-pregnancy symptoms, such as nausea and breast tenderness, while others have no early symptoms and may not realize they are pregnant. However, about one week after a missed menstrual period, a woman may experience slight, irregular vaginal bleeding that often is brownish in color. Some women mistake this bleeding for a normal menstrual period. The bleeding may be followed by colicky pain in the lower abdomen, often felt mainly on one side. A woman with these symptoms should contact her health care provider promptly or go to a hospital emergency room. Without treatment, these symptoms may be followed in several days or weeks by severe pelvic pain, shoulder pain (due to blood from a ruptured ectopic pregnancy pressing on the diaphragm), faintness or dizziness, nausea or vomiting.
How is an ectopic pregnancy diagnosed?
A suspected ectopic pregnancy can turn a happy event into a frightening health crisis for the pregnant woman. Because an ectopic pregnancy can be difficult to diagnose, she will need to undergo several tests. These can include a series of blood tests to measure the levels of a pregnancy hormone called human chorionic gonadotropin (hCG), which are often low in an ectopic pregnancy, and vaginal or abdominal ultrasound examinations to locate the pregnancy. If these tests do not show whether or not there is an ectopic pregnancy, the doctor may need to view the abdominal organs directly with a thin, flexible viewing instrument called a laparoscope, which is inserted through a tiny incision in the abdomen while the woman is under general anesthesia.
How is an ectopic pregnancy treated?
If the doctor finds an ectopic pregnancy, the embryo (which, with very rare exceptions, cannot survive), must be removed so that it does not endanger the woman life. If the embryo continues to grow, it can cause the fallopian tube to rupture, resulting in life-threatening internal bleeding.
An ectopic pregnancy usually must be removed surgically. When the pregnancy is diagnosed before the fallopian tube ruptures, the doctor usually makes a tiny incision in the fallopian tube and removes the embryo, saving the fallopian tube and improving the outlook for future fertility. Or, instead of surgery, a woman may be treated with the cancer drug methotrexate, which dissolves the pregnancy, and also saves the fallopian tube. Treatment with methotrexate is most effective in the first six weeks of pregnancy. If the tube has become stretched out or it has ruptured and bleeding has begun, the doctor may have to remove part or all of the fallopian tube.
Today, most ectopic pregnancies are diagnosed in the first eight weeks of pregnancy, usually before the tube has ruptured. This reduces the risk to the pregnant woman; however, the couple still must face the loss of the pregnancy.
What are the risk factors for ectopic pregnancy?
The number of ectopic pregnancies in this country has increased five-fold over the past twenty years. This is largely due to the skyrocketing rate of sexually transmitted infections, such as chlamydia, which often leads to pelvic inflammatory disease and scarring of the fallopian tubes. Other risk factors include fertility drugs, pregnancy after failed tubal sterilization, previous operations on the fallopian tube, endometriosis (when uterine tissue implants outside the uterus), and cigarette smoking. However, in most women, the cause of an ectopic pregnancy is unknown.
What is the outlook for future pregnancies?
If a woman has had an ectopic pregnancy, her outlook for a future healthy pregnancy is usually quite good. Studies suggest that about 60 to 80 percent of women who have both fallopian tubes are able to have a normal pregnancy. These rates are about the same whether a woman has been treated surgically or with methotrexate. More than 40 percent of women who have had one fallopian tube removed during treatment for ectopic pregnancy go on to have healthy pregnancies. However, women who have had an ectopic pregnancy have a 7 to 15 percent chance of it happening again, so they need to be monitored carefully when they attempt to conceive again. It is more likely to recur if a woman had surgery after the tube had already ruptured, or if she has a history of pelvic inflammatory disease.
What is a molar pregnancy?
In a molar pregnancy, the early placenta develops into a mass of cysts (called a hydatidiform mole) that resemble a bunch of white grapes. The embryo either does not form at all or is malformed and cannot survive. About one in 1,000 pregnancies is molar. Women who are over age 40 or who have had two or more miscarriages are at increased risk of molar pregnancy.
There actually are two types of molar pregnancy, complete and partial. With a complete mole, there is no embryo and no normal placental tissue. With a partial mole, there may be some normal placenta and the embryo, which is abnormal, begins to develop.
Both types of molar pregnancy arise from an abnormal fertilized egg. In a complete mole, all of the fertilized egg chromosomes (tiny thread-like structures in cells that carry our genes) come from the father. Normally, half come from the father, and half from the mother. Shortly after fertilization, the chromosomes from the mother egg are lost or inactivated, and those from the father are duplicated. In most cases of partial mole, the mother 23 chromosomes remain, but there are two sets of chromosomes from the father (so the embryo has 69 chromosomes instead of the normal 46). One way this happens is fertilization of an egg by two sperm cells.
Molar pregnancy poses a threat to the pregnant woman when the mole penetrates deep into the uterine wall, which can result in heavy bleeding. Occasionally, a mole can turn into a choriocarcinoma, a rare pregnancy-related form of cancer.
What are the symptoms of a molar pregnancy?
A molar pregnancy may start off like a normal pregnancy. Then, around the 10th week of pregnancy, vaginal bleeding, which often is dark brown in color, usually occurs. Other common symptoms include: severe nausea and vomiting, abdominal cramps (from a uterus that is too large due to the increasing number of cysts), and high blood pressure.
How is a molar pregnancy diagnosed?
An ultrasound examination can diagnose a molar pregnancy. The doctor also will measure the levels of hCG, which often are higher than normal with a complete mole, and lower than normal with a partial mole.
How is a molar pregnancy treated?
A molar pregnancy is a very frightening experience. Not only does the woman lose a pregnancy, she learns that she has a slight risk of developing cancer. In order to protect the woman, all molar tissue must be removed from the uterus. This usually is done using a procedure called suction curettage, under general anesthesia. Occasionally, when the mole is extensive and the woman has decided against future pregnancies, a hysterectomy may be done.
After the procedure, the doctor will again measure the level of hCG. If it has dropped to zero, the woman generally needs no additional treatment. However, the doctor will continue to monitor hCG levels for one year to be sure there is no remaining molar tissue. A woman who has had a molar pregnancy should not become pregnant for one year, because a pregnancy would make it difficult to monitor hCG levels.
How often do moles become cancerous?
After the uterus is emptied, about 20 percent of complete moles and 2 percent of partial moles persist and the remaining abnormal tissue may continue to grow. This is called persistent gestational trophoblastic disease (GTD). Treatment with one or more cancer drugs cures GTD nearly 100 percent of the time. Rarely, a cancerous form of GTD called choriocarcinoma develops that spreads to other organs. Treatment with multiple cancer drugs also is very successful at treating this cancer.
What is the outlook for future pregnancies after a molar pregnancy?
If a woman has a molar pregnancy, her outlook for a future pregnancy is good. The risk that a mole will develop in a future pregnancy is only one to two percent.
Both ectopic and molar pregnancies are medical emergencies. As she undergoes diagnosis and treatment, the pregnant woman may be concerned mainly about her own health. Afterwards, the woman and her partner feel relief that she has come through the ordeal. Then grief over the loss of the pregnancy may hit them. As with any couple who has lost a pregnancy, they need time to grieve and to recover emotionally. This is a difficult time, and it may be helpful for the couple to speak with a counselor who is experienced in dealing with pregnancy loss.
Parents or other family members who have experienced the loss of a baby between conception and the first month of life can receive a free March of Dimes bereavement kit.
Berkowitz, R.S;, et al. Update on gestational trophoblastic disease. Contemporary Ob/Gyn, April 1996, pages 21-29.
Centers for Disease Control and Prevention. Ectopic Pregnancynited States, 1990-1992. Morbidity and Mortality Weekly Report, volume 44, number 3, January 27, 1995, pages 46-48.
Cunningham, F.G., et al. Ectopic pregnancy, in: Williams Obstetrics, 20th edition, Stamford, CT, 1997, pages 607-609.
Cunningham, F.G., et al. Gestational trophoblastic disease, in: Williams Obstetrics, 20th edition, Stamford, CT, 1997, pages 676-687.