Pregnancy Bliss | Reproductive Health Answers
Molar pregnancy
What is trophoblastic disease?
This is a group of conditions that occur almost exclusively in pregnancy. They range from the benign but potentially malignant hydatidiform mole (molar pregnancy) to the frankly malignant choriocarcinoma.
So what exactly is hydatidiform mole (molar pregnancy)?
This is a condition where, following conception, the baby (embryo) does not form.
Instead, placental tissue consisting only of 
vesicles (sacs filled with clear fluid)
develop. The "pregnant" woman will have normal pregnancy symptoms and body changes.
In fact, in some cases, symptoms such as nausea and vomiting may be quite pronounced
and may be the first warning of something amiss. It is important to emphasize from
the outset that molar pregnancy is not a malignant condition. It appears in this
chapter for reasons explained below.
What is in a name?
Hydatidiform mole is , well, a mouthful. It comes from the Greek word hydatis (water drop) and a Latin word mola (mass). It is a descriptive term since a typical molar pregnancy looks like a bunch of grapes or a mass of water drops.
What about a ‘partial’ mole?
The description above refers to a ‘complete’ mole which is the commonest form. The other variety is what is known as a ‘partial’ mole. In this, there is evidence of embryo development but the embryo dies early. The placental tissue then undergoes the changes described above leading inevitably to a miscarriage. It is exceedingly rare for malignant transformation to follow a partial mole. A persistent or invasive (non-malignant) mole can follow a partial mole and that may be treated with a course of chemotherapy.
What are the symptoms of molar pregnancy?
There may be exaggerated pregnancy symptoms. This is by no means always the case. More commonly, the woman will have light vaginal bleeding or a brownish discharge. More than half of such patients are found to have a uterus which feels bigger than the apparent gestation of the pregnancy. A significant proportion, however, will have the uterus feeling smaller than the gestation.
The diagnosis will be confirmed by an ultrasound scan which shows a characteristic image. Very occasionally the patient will pass some vesicles.
This is the typical appearance of a hydatidform mole (molar pregnancy). You can clearly see the fluid-filled vesicles. In a complete mole, these fill up the uterine cavity.