FORMATION IDENTICAL TWINS, IDENTICAL NO DOUBLE & TWIN SIAM
These cute twins?Formation of double fertilization of two separate eggs that (dizygotic or non-identical twins) or a fertilized ovum then divided into two (monozygotic or identical twins). There are several types of monozygotic identical twins where cell division depends on a specific day. Formation more than doubled twins or Siamese twins are also dependent on cell division.
The formation of twins - Dizygotic / non identical twinsDizygotic twins arise from two separate eggs fertilized by two sperm. The two zygotes developed into blastocysts and free stuck on the wall. Dizygotic twins are also known as dichorionic diamniotic (DCDA) in which each of the developing fetus has a chorion, and amniotic sac itself. Therefore, two placenta is formed where each fetus has its own placenta or a placenta that has been listed.
The formation of twins - Monozygotic / identical twinsFormation of monozygotic twins arise from a single fertilized ovum with a sperm, then divided into two fetuses. However, the formation of chorion, amniotic sac and fetus depends on the distribution day. Types of monozygotic twins are:
(1) monozygotic twins: Dichorionic diamniotic, DCDA (2 chorion, amniotic 2)
• Division of the zygote into two fetuses had 2 and 2 amniotic chorion in the first 3 days after fertilization. DCDA twins have 2 placenta.
(2) monozygotic twins: Monochorionic diamniotic, MCDA (1 chorion, amniotic 2)
• Division of the zygote into two fetuses have one chorion and two amniotic within 4-8 days after fertilization. MCDA twins have one placenta only.
(3) monozygotic twins: Monochorionic monoamniotic, MCMA (1 chorion, amniotic 1)
• Division of the zygote into two fetuses have one chorion and one amniotic 8-13 days after fertilization. MCMA twins also have only one placenta.
(4) Siamese Twins
• incomplete zygote division into two fetuses had mated 1 and 1 amniotic chorion after 13 days of fertilization. Siamese twins also have only one placenta.