The classic signs and symptoms of complete mole are:

• Vaginal bleeding: Up to 50% of the cases of complete mole have vaginal bleeding, making it the most common classical symptom of this condition.
• Nausea and vomiting: High levels of hCG (human chorionic gonadotropin) lead to severe nausea and vomiting.
• Hyperthyroidism: hCG (human chorionic gonadotropin) as well as other thyroid stimulating substances (such as thryrotropin) produced by the trophoblast can cause the signs and symptoms of hyperthyroidism.
• Absence of fetal heart sounds

Incomplete moles do not give rise to the above mentioned classical signs and symptoms. Vaginal bleeding and absence of fetal heart sounds mimic an incomplete or missed abortion.
The use of advanced imaging techniques such as high resolution ultrasonography routinely during the course of pregnancies has revolutionized the diagnosis of hydatidiform moles. As a result, molar pregnancies are now easily detected in the first trimester and the classical clinical presentation is rarely seen [8] [9].

• Pain

  In a pregnant patient, vaginal bleeding and abdominal pain are common presentations. Molar pregnancy is an uncommon cause of abdominal pain and vaginal bleeding that should be considered. [ncbi.nlm.nih.gov]

• Anemia

  However, 75% (405/540) had significant anemia described as hemoglobin level < 10 mg/dL, and 32% (173/540) had accompanying pallor, hypotension and tachycardia. [ncbi.nlm.nih.gov]

  Complete blood count: Anemia and coagulopathy may be present in some cases of molar pregnancy. In both complete and partial moles, ultrasonography is the criterion standard for establishing the diagnosis. [symptoma.com]

  Medical Complications of Hydatidiform Mole Common complications include anemia, infection, hyperthyroidism, pregnancy-induced hypertension or pre-eclampsia, and theca lutein cysts.  Anemia : A hemoglobin of less than 10 g/dL, seen in 50% of patients [slideshare.net]

  A molar pregnancy puts you at risk for anemia, hyperthyroidism, and gestational hypertension. The abnormal tissue may grow through the lining of your uterus and into muscle. This may cause bleeding into your abdomen or pelvis. [drugs.com]

• Asymptomatic

  CONCLUSION: In our study a large proportion of molar pregnancies were asymptomatic at the time of diagnosis. This confirms earlier reports of the changing clinical presentation of HM and shows that this trend continues. [ncbi.nlm.nih.gov]

  The number of asymptomatic patients has increased, due to the use of ultrasonography at the onset of pregnancy. The use of medication that induces uterine contractions must be avoided, and vacuum aspiration should be used. [scielo.br]

  Other possible signs include neurologic symptoms (resulting from brain metastases) in a female within the reproductive age group and asymptomatic lesions on routine chest x-ray. [cancer.gov]

• Vomiting

  Nausea and vomiting: High levels of hCG (human chorionic gonadotropin) lead to severe nausea and vomiting. [symptoma.com]

  The pregnancy was unremarkable except for the complaints of excessive nausea and vomiting. [ncbi.nlm.nih.gov]

  You cannot stop vomiting. You have changes in your vision. Your heart is beating faster than usual. You have questions or concerns about your condition or care. When should I seek immediate care or call 911? You have vaginal bleeding. [drugs.com]

• Nausea

  Nausea and vomiting: High levels of hCG (human chorionic gonadotropin) lead to severe nausea and vomiting. [symptoma.com]

  The pregnancy was unremarkable except for the complaints of excessive nausea and vomiting. [ncbi.nlm.nih.gov]

  Most women have severe nausea and vomiting, vaginal bleeding, and very high blood pressure. Ultrasonography, blood tests to measure human chorionic gonadotropin (which is produced early during pregnancy), and a biopsy are done. [msdmanuals.com]

• Abdominal Pain

  In a pregnant patient, vaginal bleeding and abdominal pain are common presentations. Molar pregnancy is an uncommon cause of abdominal pain and vaginal bleeding that should be considered. [ncbi.nlm.nih.gov]

• Morning Sickness

  The symptoms of molar pregnancy, which may include vaginal bleeding, severe morning sickness, stomach cramps, and high blood pressure, typically begin around the 10th week of pregnancy. [diseaseinfosearch.org]

  Some women with a molar pregnancy have: vaginal bleeding or a dark discharge from the vagina in early pregnancy (usually in the first three months) – this may contain small, grape-like lumps severe morning sickness an unusually swollen tummy But some [nhs.uk]

• Hypertension

  All these signs suggest the possibility of trophoblastic embolisation during the intraoperative period leading to pulmonary artery hypertension (PAH) and pulmonary oedema rather than uncontrolled hyperthyroidism, as suggested by the author. [dx.doi.org]

  Once the patient had been informed of the risks, it was decided to continue the pregnancy, but termination of pregnancy was necessary at week 13 + 5 due to maternal complications consisting of hyperthyroidism, hypertension and vaginal bleeding, followed [ncbi.nlm.nih.gov]

• Tachycardia

  Intraoperative events included hypotension and tachycardia, although in general, tachycardia was prevented with antiarrhythmic agents and transfusion with a plasma expander and crystalloid fluid. [ncbi.nlm.nih.gov]

  On examination, she had tachycardia (108 BPM), a blood pressure of 146/86 mm Hg, and a regular respiration rate of 18 breaths per minute. There was no exophthalmos, and her extraocular movements were normal. [thyroid.org]

  Frequently, it occurs at the time of evacuation of a mole in patients with marked uterine enlargement. Patients present with chest pain, shortness of breath, tachypnea, tachycardia, and hypoxemia. [slideshare.net]

• Seizure

  You have a seizure. Care Agreement You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. [drugs.com]

• Vaginal Bleeding

  In a pregnant patient, vaginal bleeding and abdominal pain are common presentations. Molar pregnancy is an uncommon cause of abdominal pain and vaginal bleeding that should be considered. [ncbi.nlm.nih.gov]

  The classic signs and symptoms of complete mole are: Vaginal bleeding: Up to 50% of the cases of complete mole have vaginal bleeding, making it the most common classical symptom of this condition. [symptoma.com]

• Enlarged Uterus

  CT may show an enlarged uterus with areas of low attenuation, or hypoattenuating foci surrounded by highly enhanced areas in the myometrium. MRI MRI may demonstrate a heterogeneous mass with cystic spaces distending the uterine cavity. [radiopaedia.org]

  RESULTS AND DISCUSSION: Theca lutein cysts and hydropic degeneration of villi, enlarged uterus and empty gestational sac, intrauterine hematoma significantly prevailed in the pregnant women with the molar pregnancies. [ncbi.nlm.nih.gov]

  On exam, the uterus is larger than gestational age. Appropriate imagine is obtained. [medbullets.com]

• Vaginal Discharge

  discharge that has a foul odor [saintlukeshealthsystem.org]

  discharge that has a foul odor © 2000-2018 The StayWell Company, LLC. 800 Township Line Road, Yardley, PA 19067. [fairview.org]

  They suspect a hydatidiform mole based on symptoms, such as a uterus that is much larger than expected and a vaginal discharge of grapelike tissue. A pregnancy test is done. [msdmanuals.com]

Upon physical examination, a molar pregnancy classically appears too large for gestational age. Fetal heart sounds are also absent.
A number of laboratory investigations are also helpful in establishing a diagnosis of molar pregnancy.

• beta-hCG: beta-hCG levels are much higher in molar pregnancies as compared to normal pregnancies. hCG levels exceeding 100,000 mIU/mL are strongly suggestive of molar pregnancy.
• Serum inhibin A and activin A: Serum inhibin A and activin A are relatively newer markers for the detection of molar pregnancies. Levels of inhibin A and activin A in the serum are 7 to 10 times higher in molar pregnancies as compared to normal pregnancies [10].
• Complete blood count: Anemia and coagulopathy may be present in some cases of molar pregnancy.

In both complete and partial moles, ultrasonography is the criterion standard for establishing the diagnosis. The classical image of hydropic chorionic villi seen in these cases is referred to as snowstorm pattern.

• Trophoblastic Cells

  Hydatidiform mole (molar pregnancy) is a benign tumor of placental trophoblastic cells, which release human chorionic gonadotropin (hCG). [ncbi.nlm.nih.gov]

  A slow-growing tumor that develops from trophoblastic cells (cells that help an embryo attach to the uterus and help form the placenta) after fertilization of an egg by a sperm. A hydatidiform mole contains many cysts (sacs of fluid). [icd9data.com]

All molar pregnancies need to be aborted in order to prevent complications. The uterus is evacuated through dilatation and curettage.

If diagnosed and managed early, there is no risk of mortality in complete and partial moles.
Hydatidiform moles may give rise to malignancy (choriocarcinoma). Malignancy is more common in complete moles (15 to 20%) as compared to partial moles (2 to 3%). These malignancies however, are almost 100% curable.

There is no specific cause for the development of hydatidiform moles. It has been suggested that low animal fat and carotene in the diet may be a risk factor.

Hydatidiform moles are a very frequent complication of pregnancy. In the United States, the incidence is approximately 1 in 1200 pregnancies [1]. Molar pregnancies are more common at the extremes of reproductive age (i.e. in early teenage and close to menopause) [2] [3].

Complete and partial moles result from slightly different pathophysiological mechanisms.
Complete moles are named so because they do not contain any fetal tissue and consist only of hyperplastic trophoblastic tissues. There is marked swelling and edema in all the chorionic villi. The genotype of the mole is either 46,XX or 46,XY, the former accounting for almost 90% of the cases [4] [5].
In most of the cases, the genetic material in a complete mole is derived paternally. Such a mole is termed androgenic complete mole and is formed when an egg that has lost its chromosomes is fertilized by either one or two sperms. The former type is known as a homozygous androgenic complete mole. After a single sperm fertilizes the egg, the haploid genetic content of that sperm is duplicated. It is the more common of the two, accounting for 80% of the cases. This type of mole is always genotypically female (46,XX). On the other hand, complete moles may be formed when two sperms fertilize an egg that has lost its chromosomes. Such a mole is termed heterozygous complete mole. These moles may be 46,XX or 46,XY genotypically and account for only 20% of the cases.
Very rarely, complete moles may be even when both maternal and paternal genes are present in the fertilized egg. Failure of maternal imprinting however, suppresses the maternal genes and they fail to express themselves. Such moles are called biparental complete moles [6].
Partial moles are formed when an egg with normal chromosomal content is fertilized by two sperms to get a triploid genotype (69,XXX or 69,XXY) [7]. Partial moles often contain fetal tissues; most commonly fetal erythrocytes and vessels. Unlike complete moles, villous edema is confined to patches of chorionic villi.

Apart from maintaining a healthy level of animal fat and carotenes in the diet, there is no documented preventive measure against the development of molar pregnancies.

Gestational trophoblastic disease is a spectrum of tumor and tumor-like conditions in which there is proliferation of trophoblastic tissue. This includes hydatidiform moles, invasive moles, choriocarcinomas and placental-site trophoblastic tumor.

Hydatidiform mole (or hydatid mole) can be defined as abnormal conception characterized by excessive proliferation of placental trophoblastic tissue. The chorionic villi become swollen and edematous and form grapelike masses. Hydatidiform mole may be designated complete or incomplete depending upon the karyotype of the abnormal tissues, the fraction of villi involved and the presence of fetal tissues.

Hydatidiform mole is an abnormal pregnancy in which instead of a fetus, there is excessive growth of placental tissue. The mole grows much more rapidly than a normal fetus and it becomes necessary to abort the pregnancy and clear the uterus. Molar pregnancies are now detected very early due to advanced ultrasound imaging techniques. There is no risk for mortality. In some molar pregnancies, there is risk for the development of cancer. Such cancers however, are readily treatable.

1. Atrash HK, Hogue CJ, Grimes DA. Epidemiology of hydatidiform mole during early gestation. American journal of obstetrics and gynecology. Apr 1986;154(4):906-909.
2. Bracken MB. Incidence and aetiology of hydatidiform mole: an epidemiological review. British journal of obstetrics and gynaecology. Dec 1987;94(12):1123-1135.
3. Schorge JO, Goldstein DP, Bernstein MR, Berkowitz RS. Recent advances in gestational trophoblastic disease. The Journal of reproductive medicine. Sep 2000;45(9):692-700.
4. Wolf NG, Lage JM. Genetic analysis of gestational trophoblastic disease: a review. Seminars in oncology. Apr 1995;22(2):113-120.
5. Slim R, Mehio A. The genetics of hydatidiform moles: new lights on an ancient disease. Clinical genetics. Jan 2007;71(1):25-34.
6. Fisher RA, Hodges MD. Genomic imprinting in gestational trophoblastic disease--a review. Placenta. Apr 2003;24 Suppl A:S111-118.
7. Watson EJ, Hernandez E, Miyazawa K. Partial hydatidiform moles: a review. Obstetrical & gynecological survey. Sep 1987;42(9):540-544.
8. Mangili G, Garavaglia E, Cavoretto P, Gentile C, Scarfone G, Rabaiotti E. Clinical presentation of hydatidiform mole in northern Italy: has it changed in the last 20 years? American journal of obstetrics and gynecology. Mar 2008;198(3):302 e301-304.
9. Soto-Wright V, Bernstein M, Goldstein DP, Berkowitz RS. The changing clinical presentation of complete molar pregnancy. Obstetrics and gynecology. Nov 1995;86(5):775-779.
10. Florio P, Severi FM, Cobellis L, et al. Serum activin A and inhibin A. New clinical markers for hydatidiform mole. Cancer. May 15 2002;94(10):2618-2622.