Essay On Siamese Twins

The term Siamese twins is used on individuals that are of a single gestation . Those twins whose bodies are still conjoined after birth. This tends to occur in one of every 200,000 births, 50% of the cases are born dead and 75% belong to the female gender . The percentage of survival in Siamese twins ranges between 5% and 25%. The origin is not yet well defined, but it is thought that Siamese twins are the result of an aberration in the process of the formation of monozygotic twins, i.e. twins of the product of the same ovum and the same sperm. In fact, monozygous twins are in themselves considered an aberration of the normal development, therefore, the Siamese represent a defect even more severe in which single ovum twin fails in its complete separation. The incomplete separation is seen as the result of a partial replication that occurs in the embryonic disk before the third week of intrauterine life. The division of embryos of normal twins typically occurs in the first ten days after fertilization, however in case of Siamese twins this …show more content…
In order to reduce the volume of blood, the receiver twin increases the amount of urine produced. This leads to the bladder increasing to a large size which can be seen on ultrasound, and also too much amniotic fluid will be around this twin. This is known as polyhydramnios. At the same time, the donor twin produces less urine than normal and the amniotic fluid that surrounds it is greatly reduced or even disappears. This is known as oligohydramnios . As the disease progresses, the donor produces so little urine that it is possible not see the bladder in the ultrasound. The donor twin is wrapped in its amniotic membrane. Often, the polyhydramnios the recipient twin is the first thing the patient notices due to the sudden increase in the size of the