Ectopic and molar pregnancy
While most pregnancies result in the birth of a healthy baby, occasionally a pregnancy goes wrong 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.
Up to 1 pregnancy in 50 is ectopic, which means “out of place” (1, 2). 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.
Some women with an ectopic pregnancy start out with typical early-pregnancy symptoms, such as nausea and tender breasts. Others have no early symptoms and may not know they are pregnant.
However, about 1 week after a missed menstrual period, a woman may experience slight, irregular vaginal bleeding that may be 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.
An ectopic pregnancy can be difficult to diagnose, so the woman needs to have several tests. These include:
- A pelvic exam
- A series of blood tests to measure the levels of a pregnancy hormone called human chorionic gonadotropin (hCG). Levels of this hormone often are low in an ectopic pregnancy.
- A vaginal or abdominal ultrasound to locate the pregnancy. A vaginal ultrasound often is used because it can show the pregnancy earlier than an abdominal ultrasound.
If these tests do not confirm an ectopic pregnancy, the provider may need to empty the uterus (a procedure called dilation and curettage or D&C) to determine whether the woman has had a miscarriage or an ectopic pregnancy.
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.
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. Most ectopic pregnancies are diagnosed in the first 8 weeks of pregnancy, usually before the tube has ruptured.
There are two treatments for ectopic pregnancy:
- Medication: If the pregnancy is small and the tube has not ruptured, a woman may be treated with a drug called methotrexate. The drug usually is given as a single shot, though some women may need more than one injection. Methotrexate stops growth of the pregnancy and saves the fallopian tube. The woman’s body gradually absorbs the pregnancy.
- Surgery: 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 tube. If an ectopic pregnancy is diagnosed after the fallopian tube has become stretched, or if the tube has ruptured and bleeding has begun, the provider may have to remove part or all of the fallopian tube.
After either of these treatments, the provider monitors the woman for several weeks with blood tests for hCG until levels of the hormone return to zero.
The most significant risk factor for ectopic pregnancy is sexually transmitted diseases (STDs), such as chlamydia. STIs can lead to pelvic inflammatory disease and scarring of the fallopian tubes. Damage to the fallopian tubes increases the risk of ectopic pregnancy. Other risk factors include (1, 2, 3):
- Previous ectopic pregnancy
- Fertility drugs and assisted reproductive techniques (such as in vitro fertilization)
- Pregnancy after failed tubal sterilization
- Previous operations on the fallopian tube
- Endometriosis (when uterine tissue implants outside the uterus)
- Exposure to the drug DES (diethylstilbestrol) in her mother’s pregnancy
- Cigarette smoking
For most women, the cause of an ectopic pregnancy is unknown (3).
Many women who have had an ectopic pregnancy can have healthy pregnancies in the future. Studies suggest that about 50 to 80 percent of women who have had an ectopic pregnancy are able to have a normal pregnancy (2, 3). The rates are about the same whether a woman has been treated surgically or with methotrexate (1).
Women who have had an ectopic pregnancy have about a 10 percent chance of it happening again, so they need to be monitored carefully when they attempt to conceive again (2).
In a molar pregnancy, the early placenta develops into an abnormal mass of cysts (called a hydatidiform mole) that resembles 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 (4).
There are two types of molar pregnancy:
- Complete mole: There is no embryo and no normal placental tissue.
- Partial mole: There is an abnormal embryo, and there may be some normal placental tissue. With a partial mole, the embryo begins to develop.
Both types of molar pregnancy are caused by 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 (4, 5). 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). This can happen when the chromosomes from the father are duplicated or if two sperm fertilize an egg (4, 5).
Molar pregnancy poses a threat to the pregnant woman because it can occasionally result in a rare pregnancy-related form of cancer called choriocarcinoma.
A molar pregnancy may start off like a normal pregnancy. Around the tenth week, abnormal vaginal bleeding, which often is dark brown in color, usually occurs. Other common symptoms include:
- Severe nausea and vomiting
- Rapid uterine growth (due to the increasing number of cysts)
- High blood pressure
- Cysts on the ovaries
Providers use an ultrasound to diagnose a molar pregnancy. The provider also measures the levels of hCG, which often are higher than normal with a molar pregnancy.
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 with a D&C. Occasionally, when the mole is extensive and the woman has decided against future pregnancies, a woman may have a hysterectomy.
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 continues to monitor hCG levels for 6 months to 1 year to be sure there is no remaining molar tissue (4). A woman who has had a molar pregnancy should not become pregnant again for 6 months to 1 year, because a pregnancy would make it difficult to monitor hCG levels (4).
After the uterus is emptied, about 20 percent of complete moles and less than 5 percent of partial moles persist. The remaining abnormal tissue may continue to grow (4). This is called persistent gestational trophoblastic disease (GTD).
Treatment with one or more cancer drugs cures persistent GTD nearly 100 percent of the time (4). Rarely, a cancerous form of GTD, called choriocarcinoma, develops and spreads to other organs. Use of multiple cancer drugs usually is successful at treating this cancer.
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 (4, 5).
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.
Parents or other family members who have lost a baby because of ectopic or molar pregnancy may want to read the bereavement information provided on this Web site.
The Maternal and Child Health Library at Georgetown University provides information on infant death and pregnancy loss.
Most common questions
How do you know if you’re having a miscarriage?
Signs of a miscarriage can include vaginal spotting or bleeding, abdominal pain or cramping, and fluid or tissue passing from the vagina. Although vaginal bleeding is a common symptom of miscarriage, many women have spotting early in their pregnancy but don’t miscarry. But if you’re pregnant and have bleeding or spotting, contact your health care provider right away.
What is dilation and curettage?
Dilation and curettage (also called D&C) is when a doctor removes tissue from the lining of a woman's uterus. Dilation ("D") is a widening of the cervix to allow medical instruments into the uterus. Curettage ("C") is the scraping of the walls of the uterus.
Some women have a D&C after a miscarriage to remove tissue. Providers also use D&C to treat heavy bleeding or to help diagnose infection, cancer and other diseases.
After a D&C, you can return to your regular activities as soon as you feel better, maybe even the same day. You may have vaginal bleeding, pelvic cramps and back pain for a few days after the procedure. Talk to your provider about medicine you can take for pain. Don’t use tampons or have sex for 1 to 2 weeks after the procedure.
When can I try to get pregnant again?
For most women, it's best to wait at least 18 months before getting pregnant again. This amount of time is best if you miscarry, or if your baby is stillborn, or if your baby dies after birth. Waiting this long gives your body enough time to heal between pregnancies. Also, giving yourself this time may help you feel less worried about your next pregnancy. Depending on your age or other medical reasons, you may not be able to wait this long. Talk to your provider about what's right for you.