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 1 pregnancy in 50 is ectopic (1, 2, 3), 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 implants in the woman's 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. 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 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, dizziness, nausea or vomiting.
How is an ectopic pregnancy diagnosed?
Because an ectopic pregnancy can be difficult to diagnose, the woman will need to undergo several tests. These 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 confirm an ectopic pregnancy, the provider may need to empty the uterus (a procedure called a dilation and curettage or D&C) to determine whether the woman has had a miscarriage or an ectopic pregnancy (2). Occasionally, the provider may need to view the abdominal organs directly with a thin, flexible instrument called a laparoscope, which is inserted through a small incision in the abdomen while the woman is under general anesthesia.
How is an ectopic pregnancy treated?
If the provider finds an ectopic pregnancy, the embryo (which cannot survive) must be removed so that it does not endanger the woman's life. If the embryo continues to grow, it can cause the fallopian tube to rupture, resulting in life-threatening internal bleeding.
An ectopic pregnancy often must be removed surgically. When an ectopic pregnancy is diagnosed before the fallopian tube ruptures, the provider usually makes a tiny incision in the fallopian tube and removes the embryo, preserving the fallopian tube.
If the pregnancy is small and the tube has not ruptured, a woman may be treated with a drug called methotrexate instead of surgery. Methotrexate stops growth of the pregnancy and saves the fallopian tube. After either of these treatments, a woman should be monitored for several weeks with blood tests for hCG until levels of the hormone return to zero.
If ectopic pregnancy is diagnosed after the fallopian tube has become stretched, or it has ruptured and bleeding has begun, the provider may have to remove part or all of the fallopian tube.
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 woman still must face the loss of the pregnancy.
What are the risk factors for ectopic pregnancy?
The most significant risk factor for ectopic pregnancies is sexually transmitted infections, such as chlamydia, which often lead 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, and endometriosis (when uterine tissue implants outside the uterus) (1, 6). In many 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 50 to 80 percent of women who have had an ectopic pregnancy are able to have a normal pregnancy (3, 4). These rates are about the same whether a woman has been treated surgically or with methotrexate. However, women who have had an ectopic pregnancy have an 8 to 14 percent chance of it happening again, so they need to be monitored carefully when they attempt to conceive again (4). 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 1 in 1,500 pregnancies is molar (7). Women who are over age 40 or who have had a previous molar pregnancy are at increased risk of molar pregnancy (8).
There 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's chromosomes (tiny thread-like structures in cells that carry genes) come from the father (8). Normally, half come from the father and half from the mother. In a complete mole, shortly after fertilization, the chromosomes from the mother's egg are lost or inactivated, and those from the father are duplicated. In most cases of partial mole, the mother's 23 chromosomes remain, but there are two sets of chromosomes from the father (so the embryo has 69 chromosomes instead of the normal 46) (8). One way this happens is fertilization of an egg by two sperm cells.
Molar pregnancy poses a threat to the pregnant woman because the condition 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. Around the tenth week, 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 provider also measures 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 frightening experience. Not only does the woman lose a pregnancy, she learns that she has a slight risk of developing cancer. To protect the woman, all molar tissue must be removed from the uterus. This usually is done using a D&C under general anesthesia. Occasionally, when the mole is extensive and the woman has decided against future pregnancies, a hysterectomy may be performed.
After mole removal, the provider again measures the level of hCG. If it has dropped to zero, the woman generally needs no additional treatment. However, the provider will continue to monitor hCG levels for six months to one year to be sure there is no remaining molar tissue (7). A woman who has had a molar pregnancy should not become pregnant for six months to one year, because a pregnancy would make it difficult to monitor hCG levels (7).
How often do moles become cancerous?
After the uterus is emptied, about 20 percent of complete moles and less than 5 percent of partial moles persist, and the remaining abnormal tissue may continue to grow (7, 8). 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 and spreads to other organs. Use of multiple cancer drugs is 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 1 to 2 percent (7).
Both ectopic and molar pregnancies are medical emergencies. As the pregnant woman undergoes diagnosis and treatment, she may be concerned mainly about her own health. Afterwards, the woman and her partner may feel relief that she has come through the ordeal. Finally, they may feel grief over the loss of the pregnancy. 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.
Resources
Parents or other family members who have experienced the loss of a baby because of ectopic or molar pregnancy may want to read the bereavement information provided on this Web site.
