Gestational Trophoblastic Disease
Rare tumors that develop from placental tissue in pregnancy
Quick Facts
- Type: Pregnancy-related (gestational) tumors
- Most common form: Hydatidiform mole (molar pregnancy)
- Key marker: hCG (pregnancy hormone) level
- Outlook: Highly treatable, often curable
Overview
Gestational trophoblastic disease (GTD) is a group of rare conditions in which cells that would normally develop into the placenta grow abnormally inside the uterus. Most forms begin during or shortly after a pregnancy, including pregnancies that do not develop into a baby.
The most common type is a molar pregnancy, also called a hydatidiform mole, which is usually benign. A smaller number of cases become a group of conditions called gestational trophoblastic neoplasia, which can spread but generally responds very well to treatment. Overall, GTD is one of the most treatable and curable groups of tumors.
Symptoms
Symptoms often appear early in what seems to be a normal pregnancy. The most common include:
- Vaginal bleeding during early pregnancy, sometimes with grape-like tissue passed
- A uterus that grows faster or larger than expected for the stage of pregnancy
- Severe nausea and vomiting
- Pelvic pain or pressure
- Very high pregnancy hormone (hCG) levels
- Occasionally, signs of an overactive thyroid or high blood pressure early in pregnancy
Because these signs overlap with other pregnancy problems, they should always be evaluated by a clinician.
Causes
GTD arises from problems during fertilization that lead to abnormal growth of trophoblast cells, the cells that normally form the placenta.
- Complete molar pregnancy: Occurs when an egg with no genetic material is fertilized, so no fetus develops and only abnormal placental tissue grows.
- Partial molar pregnancy: Occurs when an egg is fertilized by two sperm or duplicated genetic material, producing abnormal tissue and a fetus that cannot survive.
- Persistent or invasive forms: Sometimes molar tissue does not fully clear or, rarely, develops into a tumor that can grow into the uterine wall or spread.
These changes happen by chance and are not caused by anything a person did before or during pregnancy.
Risk Factors
- Pregnancy at a younger age (under about 20) or older age (over about 35)
- A previous molar pregnancy
- A history of miscarriage
- Certain dietary or regional factors that have been linked to higher rates in some populations
Most people with these risk factors will never develop GTD, and many who develop it have no risk factors at all.
Diagnosis
GTD is usually found during evaluation of abnormal bleeding or unusual pregnancy findings.
- Ultrasound: Often shows a characteristic pattern instead of a normal developing pregnancy.
- Blood hCG testing: Pregnancy hormone levels are frequently much higher than expected and are tracked over time.
- Tissue examination: After the abnormal tissue is removed, a pathologist examines it to confirm the type of GTD.
- Imaging for spread: If a neoplastic form is suspected, chest imaging or other scans may check whether it has spread, most often to the lungs.
Treatment
Treatment depends on the type of GTD and whether it has spread, but the outlook is generally excellent.
- Removal of molar tissue: Most molar pregnancies are treated with a procedure to empty the uterus (suction dilation and curettage).
- hCG monitoring: After treatment, hormone levels are followed closely until they return to normal and stay there, confirming the tissue is gone.
- Chemotherapy: For persistent or spreading disease, chemotherapy is highly effective and cures the great majority of cases.
- Hysterectomy: Rarely, removal of the uterus is considered for people who do not wish to preserve fertility or have specific high-risk disease.
Pregnancy is usually avoided for a period after treatment so that hCG levels can be used to confirm recovery.
Prevention
There is no proven way to prevent gestational trophoblastic disease, because the genetic changes that cause it happen by chance at fertilization. The most important protective step is careful follow-up:
- Attend all recommended early-pregnancy ultrasounds and check-ups
- Complete the full schedule of hCG monitoring after a molar pregnancy
- Discuss timing of future pregnancies with your care team, especially after a previous molar pregnancy
When to See a Doctor
Contact a healthcare provider promptly if you are pregnant and have vaginal bleeding, severe nausea and vomiting, or pelvic pain, or if you pass unusual tissue. These symptoms need evaluation even though many causes are not serious.
Seek urgent care for heavy vaginal bleeding, severe abdominal pain, fainting, or shortness of breath. After treatment for GTD, report any return of bleeding or pregnancy-like symptoms, since this can signal that monitoring and further treatment are needed.
Frequently Asked Questions
Is gestational trophoblastic disease cancer?
Some forms are and some are not. The most common form, a molar pregnancy, is usually benign. A smaller group, called gestational trophoblastic neoplasia, behaves like cancer and can spread, but it responds very well to treatment and is often curable.
Can I have a normal pregnancy after GTD?
Yes. Most people go on to have normal, healthy pregnancies after treatment. Doctors usually advise waiting until hCG levels have been normal for a recommended period before trying to conceive again.
Why do doctors keep checking hCG levels?
The pregnancy hormone hCG is made by trophoblastic tissue, so its level acts as a marker for the disease. Tracking hCG until it normalizes and stays normal confirms that all abnormal tissue is gone and helps catch any return early.
Did I do something to cause a molar pregnancy?
No. Molar pregnancies and other forms of GTD result from chance errors during fertilization and are not caused by anything you ate, did, or avoided. They are not a sign of poor self-care.
What is the warning sign I should never ignore?
Heavy vaginal bleeding during early pregnancy, especially with severe nausea or pelvic pain, should be evaluated right away. Seek urgent care for very heavy bleeding, fainting, or shortness of breath.
References
- American Cancer Society. Gestational Trophoblastic Disease.
- National Cancer Institute (NCI). Gestational Trophoblastic Disease Treatment.
- MedlinePlus, U.S. National Library of Medicine. Hydatidiform mole.