Molar pregnancy

The hydatidiform mole or Traubenmole ( Mola hydatidosa ) is a disorder of embryonic development in pregnancy. By extending the small placental vessels, there is a bubble-like transformation of placental with melting of the surrounding connective tissue. The trophoblast shows increased proliferation activity. A distinction is made between partial (90 %) and complete (10%) hydatidiform mole. The transitions between the destructive ( invasive ) hydatidiform mole and choriocarcinoma which are fluid and not uniform in the literature. Accompanying come to a hydatidiform mole on a child's head to large luteal cysts of the ovary, which are formed due to the high secretion of gonadotropin in the sense of hyperstimulation syndrome.

Pathogenesis

To complete ( full ) molar pregnancy occurs when the maternal chromosome set of the simple egg is lost ( by an as yet unknown mechanism ) and the paternal chromosome set is doubled. It results in a double set of chromosomes without maternal genetic material. From this developed the trophoblast only, but no embryonic tissue. In 20% of cases there is a malignancy.

For incomplete ( partial) hydatidiform mole occurs when an egg cell, which contains a simple set of DNA, is fertilized by two sperm. The result is a triploid paternal and maternal origin. From this we can develop the trophoblast and embryonic tissue.

Signs and diagnosis

Signs of a molar pregnancy can be a particularly fast-growing uterus (womb ), a highly positive pregnancy test, the absence of fetal heart tones as well as particularly strong pregnancy nausea.

The diagnosis is made on increased values ​​for the human chorionic gonadotropin ( β - hCG) and on the representation of the thickened placenta in ultrasound examinations.

Effects

In the presence of an embryo or an embryo is the result of a partial hydatidiform of fruit abortion. For the complete hydatidiform mole is due to the pathogenesis (see above ) and the uniparental double set of chromosomes, the so exclusively from the father, a normal development of the embryo is not possible. This is due to different activation or inactivation of genes by imprinting. In uniparentalem paternal set of chromosomes, individual genes are completely inactivated without resorting to the homologous maternal allele is present a functional copy. Other examples of Imprintingfehler only individual chromosomes are Prader- Willy syndrome and Angelman syndrome.

If no embryo is an increased growth of the trophoblast instead (partly also destructive to the tissue of the uterus), which can mimic an intact pregnancy.

Treatment

Due to the existing risk of degeneration of hydatid curettage or aspiration of moles must be done. This procedure should be performed as soon as possible after diagnosis. Thereafter, the blood levels of the human Choriogonadotropins (hCG ) can be controlled until it is no longer detectable. Invasive hydatidiform moles are also treated in some cases by means of chemotherapy, where they often respond well to monotherapy with methotrexate. The recurrence risk is about 1 %.