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Definition
By Mayo Clinic staffA molar pregnancy — also known as hydatidiform mole — is a noncancerous (benign) tumor that develops in the uterus. A molar pregnancy occurs when there is an extra set of paternal chromosomes in a fertilized egg. This error at the time of conception transforms what would normally become the placenta into a growing mass of cysts.
In a complete molar pregnancy, there's no embryo or normal placental tissue. In a partial molar pregnancy, there's an abnormal embryo and possibly some normal placental tissue. The embryo begins to develop but is malformed and can't survive.
A molar pregnancy can have serious complications — including a rare form of cancer — and requires early treatment.
- Early pregnancy loss: Miscarriage and molar pregnancy. American College of Obstetricians and Gynecologists. http://www.acog.org/publications/faq/faq090.cfm. Accessed Sept. 29, 2011.
- Ectopic and molar pregnancy. March of Dimes. http://www.marchofdimes.com/Baby/loss_ectopic.html. Accessed Oct. 3, 2011.
- Copeland LJ, et al. Malignant diseases and pregnancy. In: Gabbe SG, et al. Obstetrics: Normal and Problem Pregnancies. 5th ed. Philadelphia, Pa.: Churchill Livingstone Elsevier; 2007. http://www.mdconsult.com/das/book/body/208746819-4/0/1528/0.html. Accessed Oct. 3, 2011.
- Garner EIO. Gestational trophoblastic disease: Management of hydatidiform mole. http://www.uptodate.com/home/index.html. Accessed Sept. 29, 2011.
- Kindelberger DW, et al. Gestational trophoblastic disease: Pathology. http://www.uptodate.com/home/index.html. Accessed Sept. 29, 2011.
- Chiang JW, et al. Gestational trophoblastic disease: Epidemiology, clinical manifestations and diagnosis. http://www.uptodate.com/home/index.html. Accessed Sept. 29, 2011.
- Garner EIO. Malignant gestational trophoblastic disease: Staging and treatment. http://www.uptodate.com/home/index.html. Accessed Sept. 29, 2011.
- Kavanagh JJ, et al. Gestational trophoblastic disease: Hydatidiform mole, nonmetastatic and metastatic gestational trophoblastic tumor: Diagnosis and management. In: Katz VL, et al. Comprehensive Gynecology. 5th ed. Philadelphia, Pa.: Mosby Elsevier; 2007. http://www.mdconsult.com/das/book/body/208746819-4/0/1524/0.html. Accessed Oct. 5, 2011.
- Dilation and curettage. American College of Obstetricians and Gynecologists. http://www.acog.org/publications/faq/faq062.cfm. Accessed Oct. 5, 2011.
- Al-Hussaini TK, et al. Recurrent pregnancy loss due to familial and non-familial habitual molar pregnancy. International Journal of Gynecology and Obstetrics. 2003;83:179.
- Soper JT, et al. Diagnosis and treatment of gestational trophoblastic disease: ACOG practice bulletin No. 53. Gynecologic Oncology. 2004;93:575.
- Harms RW (expert opinion). Mayo Clinic, Rochester, Minn. Oct. 9, 2011.
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