A molar pregnancy is an abnormality of the placenta, caused by a problem when the egg and sperm join together at fertilization.

Types

Complete - this happens when the egg contains a duplicate number of the father's chromosomes (therefore, 46 in total), but no maternal chromosomes. If this happens, no embryo will develop, and neither the amniotic sac nor regular placental tissue will form. A mass of cysts will form instead.

Partial mole - this happens when the egg has double the amount of the father's chromosomes (therefore, 46 in total), and the mother's usual 23 chromosomes. In this situation, the egg will end up with 69 chromosomes in total. If this occurs, the embryo will start to develop, but is abnormal and will never grow into a healthy, full-term baby.

This is more common in older women and in certain geographic locations.

This depends on the part of the world. In the US, the chances are about 1/1000. In Asia, it is 3 times higher, though no one really knows why.

Women over 40 have an increased risk than younger women.

If you've already experienced this condition, your chances increase to 1/100.

What Are The Symptoms?

* vaginal spotting/bleeding
* nausea/vomiting
* enlarged ovaries
* abnormally high level of hcg in the blood
* "cluster of grapes" shown on an ultrasound
* more rarely - preeclampsia Treatment

It is vital that a woman who has suffered a molar pregnancy be monitored by her doctor since this can re-occur. Tests will be conducted on a regular basis, such as x-rays, frequent vaginal and uterus examinations, and frequent blood tests to test for hcg levels.

If a mole comes back, chemotherapy may be required to prevent these placental cells from spreading to other organs like cancer. Thankfully, this only happens in about 20% of complete molar pregnancies. It's more uncommon with partial moles.

Some doctors ask women to wait 1 year before trying to conceive again. This is because a rise in hcg levels may indicate a normal pregnancy when the patient is trying to get pregnant, or it could indicate a re-occurance. Waiting 1 year will avoid this confusion.