Molar Pregnancy

Molar Pregnancy.

A molar pregnancy which is medically known as a Hydatidiform mole is an

abnormality of the placenta which is caused when the sperm fertilizes an egg without

a nucleus. A baby is not always present and the cells that line the gestational sac begin

to convert into a growth resembling a cluster of watery grapes, thus signifying an

abnormal placenta. Hydatid literally means a watery cyst. There are two types of

molar pregnancy, complete and partial.

A complete molar pregnancy occurs when a sperm fertilizes an empty egg with no

nucleus and only the placenta is formed. As the placenta grows the pregnancy

hormone HCG is produced making the mother believe that she is pregnant with a

healthy baby. An ultrasound will show only a placenta. No baby will grow. Normally

a developing babies chromosomes are made up of half from the mother and half from

the father. In the case of a complete molar pregnancy the fertilized eggs chromosomes

come from the father. Shortly after fertilization has taken place the chromosomes

from the mother’s egg are inactivated and the father’s chromosomes are duplicated.

A partial molar pregnancy occurs when an egg is fertilized by two sperm. Instead of

forming twins, an abnormal fetus and abnormal placenta will develop. As the baby

has too many chromosomes it normally always dies within the womb and is

consumed very quickly by the developing mass. In the case of a partial molar

pregnancy the mother’s 23 chromosomes still exist but there are two sets from the

father resulting in the embryo having 69 chromosomes instead of 46.

About 1 in every 1000 women has a molar pregnancy. The risks of developing a

molar pregnancy are higher if the mother is under 20 years of age or over 40 years of

age and if the mother has had two or more miscarriages. If a molar pregnancy has

been experienced in the past the chances of another one occurring is about 1-2%....