Definition | Molar pregnancy – hydatidiform mole

A pregnancy molar or hydatidiform mole describes a rare form of pregnancy, not viable, without embryo which is established in theuterus. These hydatidiform moles represent approximately one in 1,000 pregnancies and one miscarriage out of 41. But these pregnancies are more frequent in developing countries. Hydatidiform moles can develop when there is an imbalance between the number of chromosomes maternal and paternal; they are therefore due to anomalies of the fertilization.

Some women have multiple pregnancies. Researchers from theMcGill University have identified Genoa which promote maternal pregnancies. The first of these genes was identified in 2007: NLRP7. Thanks to this discovery, women who have recurrent molar pregnancies can take a Review genetic. Three other genes involved in molar pregnancies were identified for 2025.

The development of a hydatidiform mole

The mole hydatidiform is an uncontrolled proliferation of trophoblast, with the formation of dilated vesicles. The placenta develops and forms a tumor who can become malignant. There are two types of hytadiform moles:

• a complete mole with fertilization of a oocyte nucleus by one or two sperm : there is no embryo. In this case, the risk of developing into a tumor is higher,
• a partial mole with the fertilization of a normal oocyte by two sperm or an abnormal sperm: there may be a beginning of fetal development.

The pregnancy is therefore a disease of the placenta, or trophoblastic disease. It can be asymptomatic, or it can be detected during a supposed miscarriage which can happen during the first trimester, accompanied by bleeding, pains… The diagnostic is done during a ultrasound, by a histological study and a dosage of the'hormone hCG. Treatment requires suctioning the mole.